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>
Ilia Denisov
ecd2bc9348