phase 6: web storage layer (KeyStore, Cache, session)

KeyStore + Cache TS interfaces with WebCrypto non-extractable Ed25519
keys persisted via IndexedDB (idb), plus thin api/session.ts that
loads or creates the device session at app startup. Vitest unit
tests under fake-indexeddb cover both adapters; Playwright e2e
verifies the keypair survives reload and produces signatures still
verifiable under the persisted public key (gateway round-trip moves
to Phase 7's existing acceptance bullet).

Browser baseline: WebCrypto Ed25519 — Chrome >=137, Firefox >=130,
Safari >=17.4. No JS fallback; ui/docs/storage.md documents the
matrix and the WebKit non-determinism quirk.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/ARCHITECTURE.md

@@ -572,7 +572,9 @@ and revoke metadata.
   the device.
 - Browser/WASM clients use WebCrypto with non-exportable storage where
   available. Loss of browser storage is acceptable and is recovered by
-  re-login.
+  re-login. The concrete browser baseline, IndexedDB schema, and
+  keystore lifecycle live in
+  [`ui/docs/storage.md`](../ui/docs/storage.md).
 
 ### Request envelope
 

ui/PLAN.md

@@ -607,24 +607,55 @@ provide a generic local cache for game state. Defines the
 TypeScript-side `KeyStore` and `Cache` interfaces that desktop and
 mobile adapters will satisfy in later phases.
 
+Decisions taken with the project owner before implementation:
+
+1. **Phase 6 stops at the storage boundary.** The PLAN previously
+   listed a Playwright check that the gateway accepts a signed
+   request. Public-key registration happens through the email-code
+   confirm endpoint, which Phase 7 wires; building a temporary
+   test-only registration path was rejected as throw-away
+   scaffolding. The live-gateway round-trip is therefore covered by
+   Phase 7's existing acceptance bullet "the first authenticated
+   Connect call after login … succeeds end-to-end" instead, which
+   cannot pass unless the Phase 6 keystore persists and signs
+   correctly.
+2. **Modern-browser baseline, no JS Ed25519 fallback.** WebCrypto
+   Ed25519 lands in Chrome ≥137, Firefox ≥130, Safari ≥17.4. Phase 7
+   surfaces a clear "browser not supported" message for older
+   engines instead of carrying a parallel `@noble/ed25519` code
+   path. The full matrix and rationale live in
+   `ui/docs/storage.md`.
+
 Artifacts:
 
-- `ui/frontend/src/platform/store/index.ts` defining `KeyStore` and
-  `Cache` interfaces
-- `ui/frontend/src/platform/store/idb-cache.ts` IndexedDB-backed
-  `Cache` using the `idb` library
-- `ui/frontend/src/platform/store/webcrypto-keystore.ts` WebCrypto
-  non-exportable Ed25519 key generation and IndexedDB handle
-  persistence
-- `ui/frontend/src/api/session.ts` thin layer that loads or creates the
-  device session at app startup
+- `ui/frontend/src/platform/store/index.ts` — public `KeyStore`,
+  `Cache`, `DeviceKeypair` interfaces and the `loadStore()`
+  resolver, with no web-specific imports in any public signature
+- `ui/frontend/src/platform/store/idb.ts` — shared `galaxy-ui`
+  IndexedDB connection (typed via `idb`'s `DBSchema`) used by both
+  the keystore and the cache
+- `ui/frontend/src/platform/store/idb-cache.ts` — IndexedDB-backed
+  `Cache` keyed by compound `[namespace, key]`
+- `ui/frontend/src/platform/store/webcrypto-keystore.ts` — WebCrypto
+  non-exportable Ed25519 key generation, structured-cloned through
+  IDB
+- `ui/frontend/src/platform/store/web.ts` — the `loadWebStore`
+  factory wired into `loadStore`
+- `ui/frontend/src/api/session.ts` thin layer with
+  `loadDeviceSession`, `setDeviceSessionId`, `clearDeviceSession`
+- `ui/frontend/src/routes/__debug/store/+page.svelte` (+ `+page.ts`
+  with `prerender = false; ssr = false;`) — dev-only debug surface
+  the Phase 6 Playwright spec drives through `window.__galaxyDebug`
+- topic doc `ui/docs/storage.md` describing the browser baseline,
+  IDB schema, keystore lifecycle, and cache contract
 
 Dependencies: Phase 5.
 
 Acceptance criteria:
 
-- a freshly generated keypair survives page reloads and produces
-  signatures that the gateway accepts;
+- a freshly generated keypair survives page reloads (the loaded
+  handle still produces signatures verifiable under the persisted
+  public key); the live-gateway round-trip is covered by Phase 7;
 - clearing site data removes the keypair, and the next request
   triggers a re-login flow;
 - `KeyStore` and `Cache` interfaces have full TypeScript types and
@@ -632,12 +663,19 @@ Acceptance criteria:
 
 Targeted tests:
 
-- Vitest unit tests for `IDBCache` with `fake-indexeddb`;
-- Vitest unit tests for `WebCryptoKeyStore` exercising generate, load,
-  sign, clear;
-- Playwright integration test: generate keypair, sign a request
-  through `WasmCore`, send through Connect, verify gateway accepts,
-  reload the page, sign another request, verify accepted.
+- Vitest unit tests for `IDBCache` with `fake-indexeddb`
+  (round-trip, namespace isolation, delete, clear-with-namespace,
+  full clear);
+- Vitest unit tests for `WebCryptoKeyStore` (generate, load,
+  signature determinism under Node WebCrypto, signature
+  verifiability after a simulated reload, third-party verify of the
+  public key, clear, fresh-keypair-after-clear);
+- Playwright e2e (`storage-keypair-persistence.spec.ts`, all four
+  projects): generate keypair, sign canonical bytes, capture the
+  signature, reload, assert the previous signature still verifies
+  under the public key (works on every engine in the baseline
+  including non-deterministic WebKit), and that
+  `clearDeviceSession` forces a fresh keypair on next load.
 
 ## Phase 7. Auth Flow UI
 
@@ -670,7 +708,10 @@ Acceptance criteria:
 - the first authenticated Connect call after login (e.g.
   `user.account.read`) succeeds end-to-end through `WasmCore` →
   `GalaxyClient` → ConnectRPC → gateway, with the response signature
-  verified and the payload decoded back to JSON;
+  verified and the payload decoded back to JSON. This bullet
+  subsumes the gateway-acceptance check originally listed in
+  Phase 6; the Phase 6 storage layer cannot pass it without
+  persisting and signing correctly;
 - a returning browser resumes the session without re-login;
 - gateway-side session revocation closes the active client immediately
   and routes back to `/login`.

ui/README.md

@@ -62,20 +62,24 @@ ui/
 ├── Makefile                wasm / ts-protos / web / mobile / desktop targets
 ├── README.md               this file
 ├── buf.gen.yaml            local-plugin TS Protobuf-ES generator
-├── docs/                   topic-based design notes
-│   ├── testing.md          per-PR / release test tiers
-│   └── wasm-toolchain.md   TinyGo build, JSDOM loading, bundle budget
-├── core/                   ui/core Go module (canonical bytes, keypair)
-├── wasm/                   TinyGo entry point exposing Core to JS
-└── frontend/               SvelteKit / Vite source
-    ├── src/api/            GalaxyClient + typed Connect client
-    ├── src/platform/core/  Core interface + WasmCore adapter
-    ├── src/proto/          generated Protobuf-ES + Connect descriptors
-    └── static/             core.wasm + wasm_exec.js (committed artefacts)
+├── docs/                    topic-based design notes
+│   ├── storage.md           web KeyStore/Cache, IDB schema, baseline
+│   ├── testing.md           per-PR / release test tiers
+│   └── wasm-toolchain.md    TinyGo build, JSDOM loading, bundle budget
+├── core/                    ui/core Go module (canonical bytes, keypair)
+├── wasm/                    TinyGo entry point exposing Core to JS
+└── frontend/                SvelteKit / Vite source
+    ├── src/api/             GalaxyClient + typed Connect client + session
+    ├── src/platform/core/   Core interface + WasmCore adapter
+    ├── src/platform/store/  KeyStore/Cache interfaces + web adapter
+    ├── src/proto/           generated Protobuf-ES + Connect descriptors
+    └── static/              core.wasm + wasm_exec.js (committed artefacts)
 ```
 
 Linked topic docs:
 
+- [`docs/storage.md`](docs/storage.md) — web KeyStore/Cache,
+  IndexedDB schema, browser baseline.
 - [`docs/wasm-toolchain.md`](docs/wasm-toolchain.md) — TinyGo build,
   loading recipe, bundle size budget.
 - [`docs/testing.md`](docs/testing.md) — Tier 1 per-PR + Tier 2

ui/docs/storage.md

@@ -0,0 +1,201 @@
+# Storage Layer (Web)
+
+The Galaxy UI client persists exactly two things on the web target:
+
+1. the device session keypair (one Ed25519 pair per browser profile),
+   and
+2. a generic local cache for game state and small bookkeeping.
+
+Both live in the same IndexedDB database `galaxy-ui`. The keypair
+private key is generated as a non-extractable WebCrypto handle and
+never appears as plain bytes in JavaScript memory or in IDB. The
+cache stores arbitrary structured-clone values and is partitioned by
+namespace.
+
+This topic doc covers the web implementation only. The platform-
+agnostic `KeyStore` and `Cache` interfaces in
+`src/platform/store/index.ts` are what the rest of the client codes
+against; later phases bring `WailsStore` and `CapacitorStore` adapters
+that satisfy the same contracts.
+
+Source-of-truth for the cross-service contract is
+[`../../docs/ARCHITECTURE.md` §15 "Transport security model"](../../docs/ARCHITECTURE.md);
+this doc only covers the web-side primitives.
+
+## Browser baseline
+
+The web keystore depends on WebCrypto Ed25519 (`{ name: 'Ed25519' }`
+in `subtle.generateKey` / `subtle.sign` / `subtle.verify` /
+`subtle.importKey('raw')`). Native support shipped relatively
+recently:
+
+| Engine    | Minimum version           | Released     |
+|-----------|---------------------------|--------------|
+| Chrome    | 137                       | May 2025     |
+| Edge      | 137                       | May 2025     |
+| Firefox   | 130                       | Sept 2024    |
+| Safari    | 17.4 (iOS 17.4 / macOS)   | March 2024   |
+
+Browsers older than the baseline above will fail at the first
+`generateKey({ name: 'Ed25519' }, ...)` call with a
+`NotSupportedError`. Phase 6 deliberately does not ship a JavaScript
+fallback (e.g. `@noble/ed25519`) — keeping the keystore on WebCrypto
+is what gives us non-extractable storage on every supported engine.
+The Phase 7 login UI surfaces a clear "browser not supported"
+message instead.
+
+### WebKit non-determinism note
+
+Pure Ed25519 (RFC 8032) signatures are deterministic: same private
+key + same message ⇒ same 64-byte signature. Most engines (Chrome,
+Firefox, Node 22's WebCrypto) follow this strictly. WebKit's
+`crypto.subtle.sign({ name: 'Ed25519' }, ...)` returns
+**non-deterministic** signatures — calls with identical inputs
+produce different signature bytes each time. The signatures still
+verify correctly under the matching public key (the protocol-level
+guarantee Galaxy depends on); only the byte-for-byte determinism
+is missing.
+
+Tests that assert "the same key signs the same message identically"
+must either pin to the Vitest path (Node WebCrypto) or be replaced
+with verify-after-sign assertions. The Phase 6 Playwright spec uses
+the verify path, which works on every engine in the baseline.
+
+## IndexedDB schema
+
+```text
+database: galaxy-ui  (version 1)
+├── object store: keypair
+│     key:   string (the constant "device")
+│     value: { privateKey: CryptoKey, publicKey: CryptoKey,
+│              publicKeyRaw: ArrayBuffer }
+└── object store: cache
+      keyPath: ["namespace", "key"]
+      value:   { namespace: string, key: string, value: unknown }
+```
+
+### `keypair` store
+
+Holds at most one row, keyed by the literal string `"device"`. The
+row carries:
+
+- `privateKey` — non-extractable Ed25519 `CryptoKey`. Persisted via
+  IndexedDB's structured-clone path; the cloned handle on load
+  signs with the same private bytes as the original (asserted by
+  the verify-after-reload Playwright test and by signature-byte
+  equality under Node).
+- `publicKey` — extractable Ed25519 `CryptoKey`. The WebCrypto spec
+  forces `extractable=true` on the public half of generated
+  asymmetric pairs regardless of the `extractable` flag passed to
+  `generateKey`.
+- `publicKeyRaw` — cached 32-byte raw export of `publicKey`. Lets
+  every `KeyStore.load()` skip an `exportKey` round-trip; the
+  `Uint8Array` view returned to callers is allocated from this
+  buffer.
+
+### `cache` store
+
+Compound-key (`[namespace, key]`) object store. Rows are
+`{ namespace, key, value }`. The `value` field is whatever the
+caller stored, round-tripped through structured-clone semantics —
+plain objects, arrays, `Uint8Array`, `Date`, etc. all survive.
+
+`Cache.clear(namespace)` walks a bounded cursor over
+`[ns, ""]..[ns, "￿"]`. The lexicographic upper bound `"￿"` is
+the largest BMP code point and acts as a sentinel above any
+realistic application-level key string.
+
+`Cache.clear()` (no argument) calls `IDBObjectStore.clear()` and
+wipes every namespace.
+
+Namespaces in current use:
+
+| Namespace | Key                  | Value type | Owner       |
+|-----------|----------------------|------------|-------------|
+| `session` | `device-session-id`  | `string`   | Phase 7+    |
+
+Phase 8 onwards will add per-feature namespaces (lobby snapshot,
+game state, fixtures, etc.). The contract is namespace-strings
+stay scoped to one feature; cross-feature reads through the cache
+are by convention disallowed.
+
+## Keystore lifecycle
+
+```text
+KeyStore.generate()  — generates a non-extractable Ed25519 keypair
+                       via subtle.generateKey, exports the public
+                       half to raw bytes, writes the row, and
+                       returns a DeviceKeypair view.
+
+KeyStore.load()      — reads the row; returns null when missing,
+                       otherwise wraps the persisted privateKey
+                       in a DeviceKeypair whose .sign(canonical)
+                       calls subtle.sign({name: 'Ed25519'}, ...).
+
+KeyStore.clear()     — deletes the row. The next load() returns
+                       null; the next generate() creates a fresh
+                       keypair.
+```
+
+`DeviceKeypair.sign` matches the `Signer` type from
+`api/galaxy-client.ts` so a session can wire the signer with
+`signer: keypair.sign.bind(keypair)`.
+
+### What counts as "site data cleared"
+
+Browser-driven clearing — the user wipes site data, runs in
+private/incognito mode that ends, or storage is evicted under
+pressure — removes the `keypair` row. The next `loadDeviceSession`
+call generates a fresh keypair; the stored `device_session_id` (if
+any) becomes orphaned and the user is forced through the email-code
+login flow again. This is documented as acceptable in
+`docs/ARCHITECTURE.md` §15 "Key storage": loss of browser storage is
+recoverable through re-login, not through key recovery.
+
+## `api/session.ts`
+
+Thin orchestration layer over `KeyStore` + `Cache`:
+
+- `loadDeviceSession(keyStore, cache)` returns
+  `{ keypair, deviceSessionId }`. The `keypair` field is always
+  populated (loaded if present, freshly generated if not). The
+  `deviceSessionId` field is `null` until Phase 7's
+  `confirm-email-code` handler stores the gateway-issued id via
+  `setDeviceSessionId`.
+- `setDeviceSessionId(cache, id)` writes the id to the `session`
+  namespace.
+- `clearDeviceSession(keyStore, cache)` wipes both the keypair and
+  the stored id. Used by the user-driven logout path and by the
+  push-event-driven revocation path.
+
+A `null` `deviceSessionId` is the signal that the session is
+unauthenticated — Phase 7 routes such users to `/login`.
+
+## Test layout
+
+- `tests/store-idb-cache.test.ts` — Vitest unit tests over the
+  cache, using `fake-indexeddb/auto` and unique per-test database
+  names so cases never share state.
+- `tests/store-webcrypto-keystore.test.ts` — Vitest unit tests over
+  the keystore, using Node 22's deterministic WebCrypto plus
+  `fake-indexeddb/auto`. Asserts byte-for-byte signature
+  determinism (which is fine under Node) and verify-after-reload.
+- `tests/e2e/storage-keypair-persistence.spec.ts` — Playwright e2e
+  test that drives the storage surface through a debug route at
+  `/__debug/store`. Asserts persistence across reload via
+  signature verification (works on every engine in the baseline,
+  including non-deterministic WebKit) and that
+  `clearDeviceSession` forces a fresh keypair on next load.
+
+The debug route is gated by `import.meta.env.DEV` and `+page.ts`
+sets `prerender = false; ssr = false;`, so the production
+static-adapter build still emits an empty shell at that path but
+the debug entry point never attaches `window.__galaxyDebug`.
+
+## Future: native targets
+
+Phase 31 (Wails) and Phase 32 (Capacitor) bring native keystores —
+Keychain on macOS / iOS, DPAPI/Credential Locker on Windows,
+libsecret on Linux, Android Keystore on Android — behind the same
+`KeyStore` interface, plus SQLite-backed `Cache` adapters. The web
+implementation here is the reference shape those adapters satisfy.

ui/docs/wasm-toolchain.md

@@ -5,6 +5,10 @@ bytes, signature verification, keypair helpers) to WebAssembly via
 **TinyGo**. The compiled artefact `core.wasm` and its companion
 runtime shim `wasm_exec.js` ship under `ui/frontend/static/`.
 
+Real Ed25519 signing happens outside WASM in a platform-specific
+keystore — see [`storage.md`](storage.md) for the web implementation
+(WebCrypto non-extractable keys + IndexedDB).
+
 ## Why TinyGo
 
 Two viable Go-to-WASM toolchains exist:

ui/frontend/package.json

@@ -11,6 +11,9 @@
     "test": "vitest run",
     "test:e2e": "playwright test"
   },
+  "dependencies": {
+    "idb": "^8.0.3"
+  },
   "devDependencies": {
     "@bufbuild/protobuf": "^2.12.0",
     "@bufbuild/protoc-gen-es": "^2.12.0",
@@ -23,6 +26,7 @@
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/svelte": "^5.2.0",
     "@types/node": "^22.0.0",
+    "fake-indexeddb": "^6.2.5",
     "jsdom": "^25.0.0",
     "playwright": "^1.59.1",
     "svelte": "^5.0.0",

ui/frontend/src/api/session.ts

@@ -0,0 +1,69 @@
+// `session.ts` is the thin layer that loads or creates the device
+// session at app startup. The keypair half is always materialised
+// (loaded from the [KeyStore], or freshly generated when the slot is
+// empty); the device-session-id half is read out of the [Cache] and
+// is `null` until Phase 7's confirm-email-code handler stores it via
+// [setDeviceSessionId]. A `null` deviceSessionId is the marker that
+// the user must run the email-code login flow.
+//
+// Phase 7 wires the production caller (a layout-level loader that
+// runs `loadDeviceSession` on first render and forwards the result
+// into the Svelte session store). Phase 6 ships the persistence
+// primitives this loader needs.
+
+import type { Cache, DeviceKeypair, KeyStore } from "../platform/store/index";
+
+export const SESSION_NAMESPACE = "session";
+export const SESSION_ID_KEY = "device-session-id";
+
+export interface DeviceSession {
+	keypair: DeviceKeypair;
+	deviceSessionId: string | null;
+}
+
+/**
+ * loadDeviceSession returns the device session for the current
+ * device. The keypair is loaded from `keyStore`; if the slot is
+ * empty, a fresh non-exportable Ed25519 keypair is generated and
+ * persisted. The returned `deviceSessionId` is `null` until Phase 7
+ * registers the public key with the gateway and persists the
+ * resulting id via [setDeviceSessionId].
+ */
+export async function loadDeviceSession(
+	keyStore: KeyStore,
+	cache: Cache,
+): Promise<DeviceSession> {
+	const existing = await keyStore.load();
+	const keypair = existing ?? (await keyStore.generate());
+	const stored = await cache.get<string>(SESSION_NAMESPACE, SESSION_ID_KEY);
+	return { keypair, deviceSessionId: stored ?? null };
+}
+
+/**
+ * setDeviceSessionId persists the device-session id returned by the
+ * gateway's confirm-email-code response so subsequent app starts can
+ * resume the session without re-login.
+ */
+export async function setDeviceSessionId(
+	cache: Cache,
+	deviceSessionId: string,
+): Promise<void> {
+	await cache.put(SESSION_NAMESPACE, SESSION_ID_KEY, deviceSessionId);
+}
+
+/**
+ * clearDeviceSession wipes both the device keypair and the stored
+ * device-session id. The next [loadDeviceSession] call will generate
+ * a fresh keypair and report `deviceSessionId: null`, forcing
+ * re-login. Used by user-driven logout and by gateway-driven
+ * revocation paths.
+ */
+export async function clearDeviceSession(
+	keyStore: KeyStore,
+	cache: Cache,
+): Promise<void> {
+	await Promise.all([
+		keyStore.clear(),
+		cache.delete(SESSION_NAMESPACE, SESSION_ID_KEY),
+	]);
+}

ui/frontend/src/platform/store/idb-cache.ts

@@ -0,0 +1,55 @@
+// `IDBCache` is the IndexedDB-backed [Cache] implementation. The
+// underlying object store uses a compound key `[namespace, key]`, so
+// `clear(namespace)` is a single bounded cursor walk rather than a
+// full-store scan.
+
+import type { IDBPDatabase } from "idb";
+import type { Cache } from "./index";
+import type { GalaxyDB } from "./idb";
+
+export class IDBCache implements Cache {
+	constructor(private readonly db: IDBPDatabase<GalaxyDB>) {}
+
+	async get<T = unknown>(
+		namespace: string,
+		key: string,
+	): Promise<T | undefined> {
+		const row = await this.db.get("cache", [namespace, key]);
+		return row?.value as T | undefined;
+	}
+
+	async put<T = unknown>(
+		namespace: string,
+		key: string,
+		value: T,
+	): Promise<void> {
+		await this.db.put("cache", { namespace, key, value });
+	}
+
+	async delete(namespace: string, key: string): Promise<void> {
+		await this.db.delete("cache", [namespace, key]);
+	}
+
+	async clear(namespace?: string): Promise<void> {
+		if (namespace === undefined) {
+			await this.db.clear("cache");
+			return;
+		}
+		// IndexedDB orders compound keys lexicographically. The pair
+		// [namespace, ""] is the lower bound and [namespace, "￿"]
+		// is the upper bound for every key whose first component equals
+		// `namespace` — ￿ is the largest BMP code point and acts
+		// as a sentinel above any realistic application-level key.
+		const range = IDBKeyRange.bound(
+			[namespace, ""],
+			[namespace, "￿"],
+		);
+		const tx = this.db.transaction("cache", "readwrite");
+		let cursor = await tx.store.openCursor(range);
+		while (cursor) {
+			cursor.delete();
+			cursor = await cursor.continue();
+		}
+		await tx.done;
+	}
+}

ui/frontend/src/platform/store/idb.ts

@@ -0,0 +1,90 @@
+// Shared IndexedDB connection used by both the WebCrypto keystore
+// and the IDB cache. Opens one versioned database (`galaxy-ui`)
+// containing two object stores:
+//
+//   keypair: out-of-line keys; we always read/write the fixed slot
+//            `device`. The row carries the `CryptoKey` handles
+//            (private + public) and a cached raw 32-byte public-key
+//            export so consumers do not call exportKey on every load.
+//   cache:   keyPath = ['namespace', 'key']; rows are
+//            { namespace, key, value } where `value` is whatever the
+//            caller stored. Compound keys give the cache cheap
+//            namespace-prefix scans without a secondary index.
+//
+// The database connection is cached per page; tests create their own
+// per-test connection by calling [openGalaxyDB] directly with a
+// distinct name so cases do not bleed state.
+
+import { openDB, type DBSchema, type IDBPDatabase } from "idb";
+
+export const DB_NAME = "galaxy-ui";
+export const DB_VERSION = 1;
+
+/** Fixed key for the single device keypair slot in the `keypair` store. */
+export const DEVICE_KEYPAIR_KEY = "device";
+
+export interface KeypairRow {
+	privateKey: CryptoKey;
+	publicKey: CryptoKey;
+	publicKeyRaw: ArrayBuffer;
+}
+
+export interface CacheRow {
+	namespace: string;
+	key: string;
+	value: unknown;
+}
+
+export interface GalaxyDB extends DBSchema {
+	keypair: {
+		key: string;
+		value: KeypairRow;
+	};
+	cache: {
+		key: [string, string];
+		value: CacheRow;
+	};
+}
+
+let cached: Promise<IDBPDatabase<GalaxyDB>> | undefined;
+
+/**
+ * dbConnection returns the cached `galaxy-ui` database connection,
+ * opening it on first call. Production callers always go through
+ * this; tests use [openGalaxyDB] with a per-test name instead.
+ */
+export function dbConnection(): Promise<IDBPDatabase<GalaxyDB>> {
+	if (!cached) {
+		cached = openGalaxyDB(DB_NAME);
+	}
+	return cached;
+}
+
+/**
+ * resetDbConnection clears the cached connection. Tests call this
+ * between cases that share `DB_NAME`; production code never does.
+ */
+export function resetDbConnection(): void {
+	cached = undefined;
+}
+
+/**
+ * openGalaxyDB opens a Galaxy UI database under the given name. The
+ * upgrade callback installs the two stores defined by [GalaxyDB] on
+ * the version-1 schema; later schema changes bump [DB_VERSION] and
+ * extend the callback in place.
+ */
+export function openGalaxyDB(name: string): Promise<IDBPDatabase<GalaxyDB>> {
+	return openDB<GalaxyDB>(name, DB_VERSION, {
+		upgrade(db) {
+			if (!db.objectStoreNames.contains("keypair")) {
+				db.createObjectStore("keypair");
+			}
+			if (!db.objectStoreNames.contains("cache")) {
+				db.createObjectStore("cache", {
+					keyPath: ["namespace", "key"],
+				});
+			}
+		},
+	});
+}

ui/frontend/src/platform/store/index.ts

@@ -0,0 +1,69 @@
+// `KeyStore` and `Cache` are the platform-agnostic persistence
+// boundaries every Galaxy UI build target (web, Wails desktop,
+// Capacitor mobile) must satisfy. The web implementation in this
+// directory backs them with WebCrypto non-exportable Ed25519 keys
+// and IndexedDB; later phases plug Wails Keychain / Capacitor
+// Preferences and SQLite behind the same interfaces without touching
+// the orchestration layer.
+//
+// Public signatures intentionally use only `Uint8Array`, `string`,
+// and `unknown` — no `CryptoKey`, no `IDBDatabase`, no `idb` symbols
+// — so callers stay portable across platforms. The `Signer` type from
+// `api/galaxy-client.ts` is structurally compatible with
+// `DeviceKeypair.sign`: the constructor takes
+// `signer: keypair.sign.bind(keypair)` (or an arrow wrapper).
+
+/**
+ * DeviceKeypair is the load-or-generate output of a [KeyStore]: the
+ * raw 32-byte Ed25519 public key in `publicKey`, and a `sign` method
+ * that produces the raw 64-byte Ed25519 signature for the given
+ * canonical bytes. The private key never leaves the platform's secure
+ * storage.
+ */
+export interface DeviceKeypair {
+	readonly publicKey: Uint8Array;
+	sign(canonicalBytes: Uint8Array): Promise<Uint8Array>;
+}
+
+/**
+ * KeyStore persists exactly one device keypair at a time. `load`
+ * returns `null` when no keypair has been generated yet; `generate`
+ * always overwrites any prior keypair with a fresh one; `clear`
+ * deletes the stored keypair so the next `load` returns `null`.
+ */
+export interface KeyStore {
+	load(): Promise<DeviceKeypair | null>;
+	generate(): Promise<DeviceKeypair>;
+	clear(): Promise<void>;
+}
+
+/**
+ * Cache is a generic local key-value store partitioned by namespace.
+ * Values flow through the platform's structured-clone equivalent, so
+ * `Uint8Array`, plain objects, nested arrays, and primitives all
+ * round-trip. `clear()` without a namespace wipes every entry; with
+ * a namespace it wipes only that namespace's keys.
+ */
+export interface Cache {
+	get<T = unknown>(namespace: string, key: string): Promise<T | undefined>;
+	put<T = unknown>(namespace: string, key: string, value: T): Promise<void>;
+	delete(namespace: string, key: string): Promise<void>;
+	clear(namespace?: string): Promise<void>;
+}
+
+export interface Store {
+	keyStore: KeyStore;
+	cache: Cache;
+}
+
+export type StoreLoader = () => Promise<Store>;
+
+import { loadWebStore } from "./web";
+
+/**
+ * loadStore resolves the [Store] implementation appropriate for the
+ * current build target. Phase 6 ships only the web adapter; later
+ * phases plug `WailsStore` and `CapacitorStore` here behind a
+ * build-time selector.
+ */
+export const loadStore: StoreLoader = loadWebStore;

ui/frontend/src/platform/store/web.ts

@@ -0,0 +1,18 @@
+// `loadWebStore` is the [StoreLoader] used by the browser build
+// target. It opens the shared `galaxy-ui` IndexedDB connection and
+// hands the same handle to both the keystore and the cache, so the
+// page boots one DB connection regardless of which subsystem touches
+// storage first.
+
+import type { Store, StoreLoader } from "./index";
+import { dbConnection } from "./idb";
+import { IDBCache } from "./idb-cache";
+import { WebCryptoKeyStore } from "./webcrypto-keystore";
+
+export const loadWebStore: StoreLoader = async (): Promise<Store> => {
+	const db = await dbConnection();
+	return {
+		keyStore: new WebCryptoKeyStore(db),
+		cache: new IDBCache(db),
+	};
+};

ui/frontend/src/platform/store/webcrypto-keystore.ts

@@ -0,0 +1,76 @@
+// `WebCryptoKeyStore` persists exactly one Ed25519 device keypair in
+// IndexedDB using the WebCrypto subtle API. The private key is
+// generated with `extractable: false`, which means even the page that
+// owns the handle cannot read out the raw bytes — only the platform's
+// signing primitive can use it. The matching public key is forced
+// extractable by the WebCrypto spec for asymmetric pairs (you cannot
+// publish a key you cannot read), and we cache its raw 32-byte
+// export alongside the handle so consumers do not pay an exportKey
+// round-trip on every page load.
+//
+// Both `CryptoKey` handles round-trip through IndexedDB's
+// structured-clone path; the non-exportable property is preserved
+// across page reloads. The browser baseline is documented in
+// `ui/docs/storage.md` (Chrome ≥137, Firefox ≥130, Safari ≥17.4).
+
+import type { IDBPDatabase } from "idb";
+import type { DeviceKeypair, KeyStore } from "./index";
+import {
+	DEVICE_KEYPAIR_KEY,
+	type GalaxyDB,
+	type KeypairRow,
+} from "./idb";
+
+const ED25519_ALG = { name: "Ed25519" } as const;
+
+export class WebCryptoKeyStore implements KeyStore {
+	constructor(private readonly db: IDBPDatabase<GalaxyDB>) {}
+
+	async load(): Promise<DeviceKeypair | null> {
+		const row = await this.db.get("keypair", DEVICE_KEYPAIR_KEY);
+		if (!row) {
+			return null;
+		}
+		return makeDeviceKeypair(row);
+	}
+
+	async generate(): Promise<DeviceKeypair> {
+		const pair = (await crypto.subtle.generateKey(
+			ED25519_ALG,
+			false,
+			["sign", "verify"],
+		)) as CryptoKeyPair;
+		const publicKeyRaw = await crypto.subtle.exportKey("raw", pair.publicKey);
+		const row: KeypairRow = {
+			privateKey: pair.privateKey,
+			publicKey: pair.publicKey,
+			publicKeyRaw,
+		};
+		await this.db.put("keypair", row, DEVICE_KEYPAIR_KEY);
+		return makeDeviceKeypair(row);
+	}
+
+	async clear(): Promise<void> {
+		await this.db.delete("keypair", DEVICE_KEYPAIR_KEY);
+	}
+}
+
+function makeDeviceKeypair(row: KeypairRow): DeviceKeypair {
+	const publicKey = new Uint8Array(row.publicKeyRaw);
+	return {
+		publicKey,
+		async sign(canonicalBytes: Uint8Array): Promise<Uint8Array> {
+			// TS 5.7+ tightened BufferSource to require an ArrayBuffer-
+			// backed view; an arbitrary Uint8Array could in principle be
+			// SharedArrayBuffer-backed. The signature input is not, so
+			// the cast is safe and keeps the public Signer type
+			// (Uint8Array) un-narrowed.
+			const signature = await crypto.subtle.sign(
+				ED25519_ALG,
+				row.privateKey,
+				canonicalBytes as BufferSource,
+			);
+			return new Uint8Array(signature);
+		},
+	};
+}

ui/frontend/src/routes/__debug/store/+page.svelte

@@ -0,0 +1,119 @@
+<script lang="ts">
+	import { onMount } from "svelte";
+	import {
+		clearDeviceSession,
+		loadDeviceSession,
+		setDeviceSessionId,
+	} from "../../../api/session";
+	import { loadStore } from "../../../platform/store/index";
+
+	interface DebugSnapshot {
+		publicKey: number[];
+		deviceSessionId: string | null;
+	}
+
+	interface DebugSurface {
+		ready: true;
+		loadSession(): Promise<DebugSnapshot>;
+		clearSession(): Promise<void>;
+		signWithDevice(message: number[]): Promise<number[]>;
+		setDeviceSessionId(id: string): Promise<void>;
+		verifyWithStoredPublicKey(
+			message: number[],
+			signature: number[],
+		): Promise<boolean>;
+	}
+
+	type DebugWindow = typeof globalThis & { __galaxyDebug?: DebugSurface };
+
+	let ready = $state(false);
+
+	function describe(err: unknown): string {
+		if (err instanceof Error) {
+			return `${err.name}: ${err.message}`;
+		}
+		return String(err);
+	}
+
+	onMount(async () => {
+		if (!import.meta.env.DEV) {
+			return;
+		}
+		const { keyStore, cache } = await loadStore();
+		const surface: DebugSurface = {
+			ready: true,
+			async loadSession() {
+				try {
+					const session = await loadDeviceSession(keyStore, cache);
+					return {
+						publicKey: Array.from(session.keypair.publicKey),
+						deviceSessionId: session.deviceSessionId,
+					};
+				} catch (err) {
+					throw new Error(`loadSession: ${describe(err)}`);
+				}
+			},
+			async clearSession() {
+				try {
+					await clearDeviceSession(keyStore, cache);
+				} catch (err) {
+					throw new Error(`clearSession: ${describe(err)}`);
+				}
+			},
+			async signWithDevice(message: number[]) {
+				try {
+					const session = await loadDeviceSession(keyStore, cache);
+					const sig = await session.keypair.sign(new Uint8Array(message));
+					return Array.from(sig);
+				} catch (err) {
+					throw new Error(`signWithDevice: ${describe(err)}`);
+				}
+			},
+			async setDeviceSessionId(id: string) {
+				try {
+					await setDeviceSessionId(cache, id);
+				} catch (err) {
+					throw new Error(`setDeviceSessionId: ${describe(err)}`);
+				}
+			},
+			async verifyWithStoredPublicKey(message, signature) {
+				try {
+					const session = await loadDeviceSession(keyStore, cache);
+					const importedPublic = await crypto.subtle.importKey(
+						"raw",
+						session.keypair.publicKey as BufferSource,
+						{ name: "Ed25519" },
+						false,
+						["verify"],
+					);
+					return await crypto.subtle.verify(
+						{ name: "Ed25519" },
+						importedPublic,
+						new Uint8Array(signature) as BufferSource,
+						new Uint8Array(message) as BufferSource,
+					);
+				} catch (err) {
+					throw new Error(`verifyWithStoredPublicKey: ${describe(err)}`);
+				}
+			},
+		};
+		(window as DebugWindow).__galaxyDebug = surface;
+		ready = true;
+	});
+</script>
+
+<main>
+	<h1>store debug</h1>
+	{#if ready}
+		<p data-testid="debug-store-ready">debug store ready</p>
+	{:else}
+		<p>booting…</p>
+	{/if}
+</main>
+
+<style>
+	main {
+		padding: 2rem;
+		font-family: system-ui, sans-serif;
+	}
+</style>

ui/frontend/src/routes/__debug/store/+page.ts

@@ -0,0 +1,12 @@
+// Debug-only route used by Playwright e2e tests in Phase 6 to drive
+// the [KeyStore]/[Cache] surface from the browser. SSR is disabled so
+// the keystore code only runs in the browser, and prerender is
+// disabled so the static-adapter build never freezes a debug page
+// into the production bundle.
+//
+// The route itself is gated at runtime by `import.meta.env.DEV`
+// inside `+page.svelte` — a production build still emits an empty
+// shell here, but the debug entry point never attaches.
+
+export const prerender = false;
+export const ssr = false;

ui/frontend/tests/e2e/storage-keypair-persistence.spec.ts

@@ -0,0 +1,129 @@
+// Verifies the Phase 6 storage layer end-to-end in real browser
+// engines: a freshly generated device keypair persists across a page
+// reload, signs deterministically with the same private key after the
+// reload, and is wiped by `clearDeviceSession` so the next load
+// generates a different keypair. The live-gateway round-trip is
+// covered by Phase 7's e2e once the email-code login flow lands;
+// this spec deliberately stops at the storage boundary.
+
+import { expect, test, type Page } from "@playwright/test";
+
+interface DebugSnapshot {
+	publicKey: number[];
+	deviceSessionId: string | null;
+}
+
+interface DebugSurface {
+	ready: true;
+	loadSession(): Promise<DebugSnapshot>;
+	clearSession(): Promise<void>;
+	signWithDevice(message: number[]): Promise<number[]>;
+	setDeviceSessionId(id: string): Promise<void>;
+	verifyWithStoredPublicKey(
+		message: number[],
+		signature: number[],
+	): Promise<boolean>;
+}
+
+declare global {
+	interface Window {
+		__galaxyDebug?: DebugSurface;
+	}
+}
+
+const CANONICAL = Array.from(new TextEncoder().encode("phase-6-canonical"));
+
+async function bootDebugPage(page: Page): Promise<void> {
+	await page.goto("/__debug/store");
+	await expect(page.getByTestId("debug-store-ready")).toBeVisible();
+	await page.waitForFunction(() => window.__galaxyDebug?.ready === true);
+}
+
+test("device keypair survives reload and produces verifiable signatures", async ({
+	page,
+}) => {
+	await bootDebugPage(page);
+	// Wipe any leftover state from a previous Playwright run that
+	// shared the same browser profile.
+	await page.evaluate(() => window.__galaxyDebug!.clearSession());
+
+	const first = await page.evaluate(async (canonical) => {
+		const sess = await window.__galaxyDebug!.loadSession();
+		const signature = await window.__galaxyDebug!.signWithDevice(canonical);
+		return { publicKey: sess.publicKey, signature };
+	}, CANONICAL);
+	expect(first.publicKey.length).toBe(32);
+	expect(first.signature.length).toBe(64);
+
+	await page.reload();
+	await expect(page.getByTestId("debug-store-ready")).toBeVisible();
+	await page.waitForFunction(() => window.__galaxyDebug?.ready === true);
+
+	const second = await page.evaluate(
+		async ({ canonical, firstSig }) => {
+			const sess = await window.__galaxyDebug!.loadSession();
+			const fresh = await window.__galaxyDebug!.signWithDevice(canonical);
+			// Signatures produced before the reload must verify under the
+			// post-reload public key. A pre-reload signature only verifies
+			// when the persisted private key is identical to the original.
+			const prevVerifies =
+				await window.__galaxyDebug!.verifyWithStoredPublicKey(
+					canonical,
+					firstSig,
+				);
+			const freshVerifies =
+				await window.__galaxyDebug!.verifyWithStoredPublicKey(
+					canonical,
+					fresh,
+				);
+			return {
+				publicKey: sess.publicKey,
+				signature: fresh,
+				prevVerifies,
+				freshVerifies,
+			};
+		},
+		{ canonical: CANONICAL, firstSig: first.signature },
+	);
+	expect(second.publicKey).toEqual(first.publicKey);
+	expect(second.prevVerifies).toBe(true);
+	expect(second.freshVerifies).toBe(true);
+});
+
+test("clearDeviceSession forces a fresh keypair on next load", async ({
+	page,
+}) => {
+	await bootDebugPage(page);
+	await page.evaluate(() => window.__galaxyDebug!.clearSession());
+	const before = await page.evaluate(async () => {
+		const sess = await window.__galaxyDebug!.loadSession();
+		return sess.publicKey;
+	});
+
+	await page.evaluate(() => window.__galaxyDebug!.clearSession());
+	const after = await page.evaluate(async () => {
+		const sess = await window.__galaxyDebug!.loadSession();
+		return sess.publicKey;
+	});
+
+	expect(after).not.toEqual(before);
+});
+
+test("setDeviceSessionId is observable through loadDeviceSession", async ({
+	page,
+}) => {
+	await bootDebugPage(page);
+	await page.evaluate(() => window.__galaxyDebug!.clearSession());
+	const before = await page.evaluate(async () => {
+		const sess = await window.__galaxyDebug!.loadSession();
+		return sess.deviceSessionId;
+	});
+	expect(before).toBeNull();
+
+	await page.evaluate(() => window.__galaxyDebug!.setDeviceSessionId("dev-1"));
+	const after = await page.evaluate(async () => {
+		const sess = await window.__galaxyDebug!.loadSession();
+		return sess.deviceSessionId;
+	});
+	expect(after).toBe("dev-1");
+});

ui/frontend/tests/store-idb-cache.test.ts

@@ -0,0 +1,80 @@
+// IDBCache unit tests under JSDOM with `fake-indexeddb` standing in
+// for the browser's IndexedDB factory. Each case opens a freshly
+// named database so state cannot leak across tests.
+
+import "fake-indexeddb/auto";
+import { afterEach, beforeEach, describe, expect, test } from "vitest";
+import type { IDBPDatabase } from "idb";
+import { IDBCache } from "../src/platform/store/idb-cache";
+import { openGalaxyDB, type GalaxyDB } from "../src/platform/store/idb";
+
+let db: IDBPDatabase<GalaxyDB>;
+let dbName: string;
+
+beforeEach(async () => {
+	dbName = `galaxy-ui-test-${crypto.randomUUID()}`;
+	db = await openGalaxyDB(dbName);
+});
+
+afterEach(async () => {
+	db.close();
+	indexedDB.deleteDatabase(dbName);
+});
+
+describe("IDBCache", () => {
+	test("round-trips a typed object", async () => {
+		const cache = new IDBCache(db);
+		const value = {
+			name: "ping",
+			payload: new Uint8Array([1, 2, 3]),
+			nested: { count: 7 },
+		};
+		await cache.put("commands", "k1", value);
+		const out = await cache.get<typeof value>("commands", "k1");
+		expect(out?.name).toBe("ping");
+		expect(out?.nested.count).toBe(7);
+		expect(Array.from(out?.payload ?? [])).toEqual([1, 2, 3]);
+	});
+
+	test("namespaces are isolated", async () => {
+		const cache = new IDBCache(db);
+		await cache.put("a", "shared-key", "from-a");
+		await cache.put("b", "shared-key", "from-b");
+		expect(await cache.get("a", "shared-key")).toBe("from-a");
+		expect(await cache.get("b", "shared-key")).toBe("from-b");
+	});
+
+	test("delete removes a single row without touching neighbours", async () => {
+		const cache = new IDBCache(db);
+		await cache.put("ns", "k1", "v1");
+		await cache.put("ns", "k2", "v2");
+		await cache.delete("ns", "k1");
+		expect(await cache.get("ns", "k1")).toBeUndefined();
+		expect(await cache.get("ns", "k2")).toBe("v2");
+	});
+
+	test("clear(namespace) wipes only that namespace", async () => {
+		const cache = new IDBCache(db);
+		await cache.put("a", "k1", "a1");
+		await cache.put("a", "k2", "a2");
+		await cache.put("b", "k1", "b1");
+		await cache.clear("a");
+		expect(await cache.get("a", "k1")).toBeUndefined();
+		expect(await cache.get("a", "k2")).toBeUndefined();
+		expect(await cache.get("b", "k1")).toBe("b1");
+	});
+
+	test("clear() wipes every namespace", async () => {
+		const cache = new IDBCache(db);
+		await cache.put("a", "k1", "a1");
+		await cache.put("b", "k1", "b1");
+		await cache.clear();
+		expect(await cache.get("a", "k1")).toBeUndefined();
+		expect(await cache.get("b", "k1")).toBeUndefined();
+	});
+
+	test("get on a missing key returns undefined", async () => {
+		const cache = new IDBCache(db);
+		expect(await cache.get("absent", "k")).toBeUndefined();
+	});
+});

ui/frontend/tests/store-webcrypto-keystore.test.ts

@@ -0,0 +1,113 @@
+// WebCryptoKeyStore unit tests under JSDOM. Uses Node 22's WebCrypto
+// (Ed25519 has been stable since Node 20) and `fake-indexeddb/auto`
+// for storage. The "simulated reload" case closes the database and
+// reopens it under the same name to prove the persisted keypair
+// still signs after the connection round-trips.
+
+import "fake-indexeddb/auto";
+import { afterEach, beforeEach, describe, expect, test } from "vitest";
+import type { IDBPDatabase } from "idb";
+import { WebCryptoKeyStore } from "../src/platform/store/webcrypto-keystore";
+import { openGalaxyDB, type GalaxyDB } from "../src/platform/store/idb";
+
+let db: IDBPDatabase<GalaxyDB>;
+let dbName: string;
+
+beforeEach(async () => {
+	dbName = `galaxy-ui-test-${crypto.randomUUID()}`;
+	db = await openGalaxyDB(dbName);
+});
+
+afterEach(async () => {
+	db.close();
+	indexedDB.deleteDatabase(dbName);
+});
+
+describe("WebCryptoKeyStore", () => {
+	test("generate produces a 32-byte raw Ed25519 public key", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		const keypair = await ks.generate();
+		expect(keypair.publicKey).toBeInstanceOf(Uint8Array);
+		expect(keypair.publicKey.length).toBe(32);
+	});
+
+	test("generate-then-load returns the same public key and a working signer", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		const fresh = await ks.generate();
+		const loaded = await ks.load();
+		expect(loaded).not.toBeNull();
+		expect(Array.from(loaded!.publicKey)).toEqual(Array.from(fresh.publicKey));
+
+		const canonical = new TextEncoder().encode("canonical-bytes");
+		const sigA = await fresh.sign(canonical);
+		const sigB = await loaded!.sign(canonical);
+		// Ed25519 is deterministic: identical (key, message) ⇒ identical
+		// signature bytes. This proves the loaded handle is the same
+		// signing key as the freshly generated one without ever
+		// touching the private bytes.
+		expect(Array.from(sigA)).toEqual(Array.from(sigB));
+	});
+
+	test("produced signature verifies under a third-party public key import", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		const keypair = await ks.generate();
+		const canonical = new TextEncoder().encode("verify-me");
+		const signature = await keypair.sign(canonical);
+		expect(signature.length).toBe(64);
+
+		const verifyKey = await crypto.subtle.importKey(
+			"raw",
+			keypair.publicKey as BufferSource,
+			{ name: "Ed25519" },
+			false,
+			["verify"],
+		);
+		const ok = await crypto.subtle.verify(
+			{ name: "Ed25519" },
+			verifyKey,
+			signature as BufferSource,
+			canonical as BufferSource,
+		);
+		expect(ok).toBe(true);
+	});
+
+	test("survives a simulated page reload", async () => {
+		const ks1 = new WebCryptoKeyStore(db);
+		const generated = await ks1.generate();
+		const canonical = new TextEncoder().encode("reload-canonical");
+		const sigBefore = await generated.sign(canonical);
+
+		db.close();
+		db = await openGalaxyDB(dbName);
+		const ks2 = new WebCryptoKeyStore(db);
+		const reloaded = await ks2.load();
+		expect(reloaded).not.toBeNull();
+		expect(Array.from(reloaded!.publicKey)).toEqual(
+			Array.from(generated.publicKey),
+		);
+		const sigAfter = await reloaded!.sign(canonical);
+		expect(Array.from(sigAfter)).toEqual(Array.from(sigBefore));
+	});
+
+	test("clear empties the slot", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		await ks.generate();
+		await ks.clear();
+		expect(await ks.load()).toBeNull();
+	});
+
+	test("load on a fresh database returns null", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		expect(await ks.load()).toBeNull();
+	});
+
+	test("generate after clear yields a different keypair", async () => {
+		const ks = new WebCryptoKeyStore(db);
+		const first = await ks.generate();
+		await ks.clear();
+		const second = await ks.generate();
+		expect(Array.from(second.publicKey)).not.toEqual(
+			Array.from(first.publicKey),
+		);
+	});
+});

ui/pnpm-lock.yaml

@@ -7,6 +7,10 @@ settings:
 importers:
 
   frontend:
+    dependencies:
+      idb:
+        specifier: ^8.0.3
+        version: 8.0.3
     devDependencies:
       '@bufbuild/protobuf':
         specifier: ^2.12.0
@@ -41,6 +45,9 @@ importers:
       '@types/node':
         specifier: ^22.0.0
         version: 22.19.17
+      fake-indexeddb:
+        specifier: ^6.2.5
+        version: 6.2.5
       jsdom:
         specifier: ^25.0.0
         version: 25.0.1
@@ -557,6 +564,10 @@ packages:
     resolution: {integrity: sha512-knvyeauYhqjOYvQ66MznSMs83wmHrCycNEN6Ao+2AeYEfxUIkuiVxdEa1qlGEPK+We3n0THiDciYSsCcgW/DoA==}
     engines: {node: '>=12.0.0'}
 
+  fake-indexeddb@6.2.5:
+    resolution: {integrity: sha512-CGnyrvbhPlWYMngksqrSSUT1BAVP49dZocrHuK0SvtR0D5TMs5wP0o3j7jexDJW01KSadjBp1M/71o/KR3nD1w==}
+    engines: {node: '>=18'}
+
   fdir@6.5.0:
     resolution: {integrity: sha512-tIbYtZbucOs0BRGqPJkshJUYdL+SDH7dVM8gjy+ERp3WAUjLEFJE+02kanyHtwjWOnwrKYBiwAmM0p4kLJAnXg==}
     engines: {node: '>=12.0.0'}
@@ -623,6 +634,9 @@ packages:
     resolution: {integrity: sha512-4fCk79wshMdzMp2rH06qWrJE4iolqLhCUH+OiuIgU++RB0+94NlDL81atO7GX55uUKueo0txHNtvEyI6D7WdMw==}
     engines: {node: '>=0.10.0'}
 
+  idb@8.0.3:
+    resolution: {integrity: sha512-LtwtVyVYO5BqRvcsKuB2iUMnHwPVByPCXFXOpuU96IZPPoPN6xjOGxZQ74pgSVVLQWtUOYgyeL4GE98BY5D3wg==}
+
   indent-string@4.0.0:
     resolution: {integrity: sha512-EdDDZu4A2OyIK7Lr/2zG+w5jmbuk1DVBnEwREQvBzspBJkCEbRa8GxU1lghYcaGJCnRWibjDXlq779X1/y5xwg==}
     engines: {node: '>=8'}
@@ -1495,6 +1509,8 @@ snapshots:
 
   expect-type@1.3.0: {}
 
+  fake-indexeddb@6.2.5: {}
+
   fdir@6.5.0(picomatch@4.0.4):
     optionalDependencies:
       picomatch: 4.0.4
@@ -1567,6 +1583,8 @@ snapshots:
     dependencies:
       safer-buffer: 2.1.2
 
+  idb@8.0.3: {}
+
   indent-string@4.0.0: {}
 
   is-potential-custom-element-name@1.0.1: {}