docs(apple): add native iOS/iPadOS app plan (apple/PLAN.md)

Design/continuity doc for the from-scratch SwiftUI iPhone+iPad app: Mac
build model, engineering decisions (min iOS 18, apple/ dir, XcodeGen+SPM,
@Observable, Swift 6 strict concurrency, SF Symbols, runtime-vector tiles),
the five determining optimizations, storage/audio/testing/crash choices,
region-aware payment seam with tracked App Store risks, and the full A-L
+ game-screen UX inventory. Delivery staged; several items tracked for
follow-up sessions.

apple/PLAN.md

@@ -0,0 +1,703 @@
+# apple/ — native iOS/iPadOS app plan
+
+Native **SwiftUI** application for iPhone and iPad, written **from scratch** (not a Capacitor
+wrapper, unlike the Android app under `ui/android`). This document is the **source of truth and
+continuity** for the effort: it lives in the repo so it travels to whatever machine does the work —
+in particular the **Mac Claude session** that does the actual building. Read it first; append to it
+as decisions land. Nothing here is final until built and verified; where a decision is locked it is
+marked **[FIXED]**.
+
+Chat with the owner is in Russian per the user-level guide; this doc, like all repo docs, is in
+**English**.
+
+---
+
+## 0. Working model — two contexts
+
+- **Mac (primary).** All real development happens in a **Claude session on the Mac**: SwiftUI code,
+  `xcodebuild`, Simulator, tests, screenshots, signing, TestFlight/App Store. The Apple toolchain is
+  native there.
+- **Linux dev-host (this repo's usual environment).** Used only to **lay groundwork for CI** (a macOS
+  runner, later) and to edit platform-agnostic Swift packages / docs. It **cannot** build or run an
+  iOS app — SwiftUI/UIKit and the iOS SDK exist only inside Xcode on macOS. (Swift the language runs
+  on Linux, but that is server-side Swift, irrelevant to iOS UI.)
+
+Consequence: the heavy loop (build/sim/screenshot) is Mac-only; keep the SwiftUI shell thin and push
+logic into plain Swift packages — good for testability regardless of host.
+
+---
+
+## 1. Tooling to install / verify on the Mac host
+
+Do this first on the Mac before any code. The owner already has Xcode + Command Line Tools + a
+simulator installed generally; the steps below are mostly **verify**, a few are **install**.
+
+### Verify (already present, confirm versions)
+- **Xcode 26** (latest) — we always build against the **newest SDK** (this is what grants the iOS 26
+  Liquid Glass appearance to standard controls; see §3). Confirm `xcodebuild -version`.
+- **Command Line Tools** — `xcode-select -p` points at the Xcode 26 toolchain.
+- **Swift 6** toolchain (bundled with Xcode 26) — `swift --version`.
+- **Simulator runtimes** — need **both**:
+  - **iOS 18** runtime (our minimum deployment target — verify the app runs/looks correct there),
+  - **iOS 26** runtime (latest — verify Liquid Glass appearance).
+  Check under Xcode ▸ Settings ▸ Platforms; install any missing runtime there.
+
+### Install (Homebrew, sudo-free where possible)
+- **XcodeGen** — `brew install xcodegen`. Generates the `.xcodeproj` from a declarative `project.yml`
+  (see §4). This is the project-management tool of record.
+- **swiftlint** and/or **swift-format** — `brew install swiftlint swift-format`. Lint/format gate.
+- *(optional, CI ergonomics)* **xcbeautify** — `brew install xcbeautify`, prettifies `xcodebuild`
+  logs. Not required for local work.
+
+### No install needed (SPM dependencies, pulled by the build)
+- **swift-snapshot-testing** (Point-Free, open-source) — snapshot tests, added as an SPM package.
+- **MetricKit** — first-party Apple framework for crash/hang/diagnostic capture; nothing to install.
+
+### Deferred / not now
+- **Apple Developer account** — in process; see the gate in §11. Not required to start (Simulator work
+  is unblocked without it).
+- **fastlane / signing automation** — only when we reach device builds / CI / release. Revisit then.
+- **macOS CI runner** (Gitea Actions on a Mac, or a cloud Mac) — the Linux-side groundwork; designed
+  later.
+
+---
+
+## 2. Fixed decisions [FIXED]
+
+| Topic | Decision |
+|---|---|
+| Language / UI | Native **SwiftUI**, from scratch; **not** Capacitor. |
+| Targets | **iPhone first**, then **iPad** (iPadOS) as a first-class target: reuse controls, adapt via layout. Possibly macOS/Catalyst far later — do not design for it now, but the `apple/` name leaves the door open. |
+| Minimum OS | **iOS 18** (reaches ~A12 devices, iPhone XS/XR and newer; wide parity). Always **build with the latest SDK** (Xcode 26). |
+| Directory | **`apple/`** in this monorepo (covers iPhone/iPad/future Mac; `ios/` too narrow, `swiftui/` names a framework not a platform). CI + docs stay co-located with the engine/wire. |
+| Project tooling | **XcodeGen** (`project.yml`) + **SPM** modules. Not a hand-managed `.xcodeproj` (merge-hostile `project.pbxproj`, opaque, non-reproducible). Tuist only if modularization outgrows XcodeGen. |
+| State management | **`@Observable`** (Observation framework), the idiomatic first-party default. **Not TCA** (heavy boilerplate, steep curve, large dependency; its benefits do not pay off at our size). Introduce a light unidirectional pattern by hand only where genuinely needed. |
+| Concurrency | **Swift 6 strict concurrency** from the start (actors / `Sendable`) — cheaper to write new than to retrofit. |
+| Localization / a11y | **First-class from the first screen**: RU/EN via String Catalogs, Dynamic Type, Dark Mode, Reduce Motion. Cheap now, expensive to retrofit. |
+| Design relationship to web | **Not a mirror of the web app.** Board + game mechanics are preserved; the rest is designed fresh with iOS-native idioms. |
+| UI philosophy | **System controls by default, custom only when necessary.** (Also "modern for free": Liquid Glass auto-applies to standard chrome on iOS 26.) |
+| Auth | **Sign in with Apple** (required by Apple when any third-party social login is offered) **plus** email / VK / Telegram / … in the usual stacked-button login. Backend already has VK/TG/email; Apple is the only new provider. Details deferred to the descriptive phase. |
+| Payments | Target **both** external rails (Robokassa / analogs, primary for RU) **and** Apple IAP, behind a **region-aware payment seam**. See §9 for the out-of-region reject risk (tracked separately). |
+| Bundle id | Reuse **`ru.eruditgame.app`** (Apple/Google namespaces are independent; one bundle id for the universal iPhone+iPad app). |
+| Design scope vs delivery | **Design/inventory scope = the full (online) app** — describe every moving part up front (online has more by design). **Implementation/delivery may stage** (stub online surfaces + stub engine first, wire real behind the same seams later). These are different axes; do not shrink the *design* to offline-first. |
+| Crash reporting | **MetricKit only** (first-party, self-hosted upload; see §8). No PLCrashReporter, no Sentry for now. |
+| Analytics | **None.** Nothing is tracked. No speculative "entry points" either (YAGNI; cheap to add later since actions centralize in `@Observable` models). Monitoring stays backend-only, as today. |
+| Onboarding | **TipKit** (first-party, iOS 17+) for the coachmark tours, not a custom dimmed-overlay reimplementation of the web coachmarks. |
+| Login (v1 surface) | **Sign in with Apple + email + guest.** VK / Telegram sign-in **deferred** to a later delivery (the login screen extends trivially with more stacked buttons). Note: with no third-party *social* provider in v1, SIWA is technically optional (email is not a social login), but we ship it deliberately; once VK/TG land it becomes mandatory. |
+| Wallet / store / ad banner | **Designed in v1** (full inventory), **delivery staged.** Keeps the region-aware payment seam + the out-of-region reject risk (§10) in scope from the start. |
+
+---
+
+## 3. Why "min iOS 18" does not freeze the design (reference)
+
+Appearance is governed by the **SDK you build against** + whether you use **standard components**,
+**not** by the deployment target. Building with the iOS 26 SDK means standard controls
+(NavigationStack, toolbars, TabView, Button, List, sheets, alerts, Form) **automatically** adopt
+Liquid Glass on iOS 26, and render the iOS 18 style on iOS 18 — with no per-version code. iOS 26-only
+APIs (e.g. `.glassEffect` on custom views) are used behind `if #available(iOS 26, *)` with a fallback.
+**Custom-drawn UI** (board, tiles, score) looks identical on every version because we own it — so the
+minimum has almost no visual cost for the game's core surface.
+
+---
+
+## 4. Proposed layout under `apple/` (to refine at setup)
+
+```
+apple/
+  project.yml            # XcodeGen spec (committed; the .xcodeproj is generated, gitignored)
+  App/                   # thin app target: @main entry, Info.plist, entitlements, asset catalog, app icon, capabilities, signing
+  Packages/              # SPM modules — the real code (merge-friendly, testable; non-UI ones buildable on Linux)
+    Domain/              #   game state, rules glue, scoring, turn model (platform-agnostic)
+    Engine/              #   Swift port of the move generator/validator/scorer + DAWG reader (parity-pinned) — later
+    Wire/                #   Connect-Swift + FlatBuffers client to the gateway (same wire as web/Android)
+    DesignSystem/        #   tokens, typography (SF), board/tile visual spec, reusable components
+    Features/            #   per-screen feature modules (views + @Observable models)
+    DataMocks/           #   mock implementations of the data protocols (the "seam"); powers Previews + e2e stubs
+  Tests/                 # or per-package tests: Swift Testing, snapshot, XCUITest
+  README.md
+```
+
+Workflow discipline (XcodeGen): the generated `.xcodeproj` is a **disposable artifact** — never edit
+project structure in the Xcode UI expecting it to persist; change `project.yml` and regenerate. Files
+are picked up by globs, not hand-listed. XcodeGen passes through arbitrary raw build settings and
+custom build phases, so custom needs are expressible; worst case escape hatches are committing the
+`.xcodeproj` or migrating to Tuist — no dead end.
+
+---
+
+## 5. Determining optimization principles [FIXED]
+
+These five shape the architecture from the start (not "add later"):
+
+1. **Push (APNs) instead of a live socket while backgrounded.** For a turn-based game we do **not** hold
+   a socket in the background; the opponent's move arrives via **push**. This is an energy-architecture
+   decision, not just notifications — it puts APNs on the critical path.
+2. **Board rendered with `Canvas`**, not a tree of ~225 `View` nodes (far cheaper in perf and memory).
+3. **Engine off the main thread** — move generation, DAWG traversal, scoring, hints run on a background
+   actor/Task; the UI stays responsive. Swift 6 concurrency enforces this.
+4. **`mmap` the dictionary (DAWG)** — memory-map, do not load the whole thing into RAM; low footprint.
+5. **Fast silent boot + spinner-less resume via cache.** Show UI instantly; move heavy init (dictionary
+   prep) off the launch path (lazy until first needed). On foreground, render the persisted state
+   immediately and **silently** re-establish the stream, reconciling deltas — no blocking overlay. (Same
+   spirit as the Android native "silent+fast boot" and the web "offline return-online poll".)
+
+### Lifecycle / background (the mechanism behind #1 and #5)
+`ScenePhase`: on `.background`/`.inactive` tear down the live stream, stop timers, release resources; on
+`.active` resume from cache + silent reconnect. Respect **Low Data Mode / cellular**
+(`NWPathMonitor.isConstrained/isExpensive`). Batch network to avoid keeping the radio awake (radio tail).
+
+---
+
+## 6. Hygiene practices (apply as we go)
+
+- **Memory warnings** — purge caches; watch for retain cycles (`[weak self]` around streams/observation).
+- **Kill any animation while backgrounded** (do not tick the turn clock in the background).
+- **Low Power Mode** (`ProcessInfo.isLowPowerModeEnabled`) — trim animations/background activity.
+- **Reduce Motion** (`accessibilityReduceMotion`) — drop lavish animations (accessibility **and** battery).
+- **Thermal state** — reduce load under throttling.
+- Let the screen sleep; no needless wake locks. No sensors (geo/motion) — none are needed.
+
+---
+
+## 7. Storage — persist eagerly, do not trust `willTerminate` [FIXED]
+
+There is **no reliable destructive callback** on iOS: `willTerminate` is often **not** called (swipe
+force-kill, memory kill happen silently). Relying on catching a "destroy" event is a trap.
+
+Pattern: **persist on the way to background** (`scenePhase → .inactive/.background`); snapshot the state
+that matters (in-progress tile placement on the board, an uncommitted move). For the uncommitted
+placement, also persist **incrementally** on meaningful changes (a tile placed / removed), **coalesced**
+(not on every drag pixel). Data volume is tiny, writes are cheap. Store: SwiftData or plain file/SQLite —
+decide at implementation. Net effect: even a silent kill loses nothing; the last valid state is on disk.
+
+---
+
+## 8. Testing [FIXED — take all three layers]
+
+The mock **seam** (protocol-backed data access with `DataMocks`) is both the Preview data source **and**
+the e2e stub mechanism.
+
+1. **Unit — Swift Testing** (`import Testing`, `@Test`, `#expect`): domain/logic, engine **parity golden
+   tests**, wire **codec** tests, view-models. Pure (non-UI) SPM packages are **Linux/CI-buildable** — a
+   slice of tests can run in the ordinary CI without a Mac.
+2. **Snapshot — swift-snapshot-testing**: visual regression of SwiftUI views against reference images
+   (fixed simulator device for determinism). Valuable for a from-scratch design.
+3. **e2e — XCUITest against the mock seam**: the native analogue of the web Playwright mock e2e. The app
+   launches with a launch argument that switches to `DataMocks`; the whole UI is driven deterministically
+   with no server. Runs on the Mac runner in CI.
+
+Lesson carried from web: the mock e2e **bypasses the real network**, so wire/codec bugs are **not** caught
+there — they need the **codec unit tests**.
+
+---
+
+## 9. Crash reporting & analytics [FIXED]
+
+- **Crashes: MetricKit.** `MXMetricManager` delivers crash/hang/CPU/disk diagnostics to the app; we
+  **upload the payload to our own backend** and view it in the existing **Grafana/logs** contour — fully
+  self-hosted, zero third-party, no paid service. Apple's Xcode Organizer / App Store Connect also provides
+  aggregated crashes for TestFlight/release builds for free.
+  - **Operational requirement:** crashes are unreadable without **symbolication** → CI **must archive the
+    `dSYM`** for every build/release (artifact), else reports are raw addresses.
+- **Analytics: none** (see §2). No tracking, no ATT prompt, no IDFA — cleaner privacy labels as a bonus.
+
+---
+
+## 10. Payments — region-aware seam, out-of-region reject risk (tracked)
+
+- Target **both** external rails (Robokassa/analogs, primary for RU) and Apple IAP, behind a **region-aware
+  payment seam** (distribution region is set per-country in App Store Connect).
+- **The RU situation is a genuine grey/in-flux area:** Apple has effectively disabled IAP for RU accounts
+  while external merchants are not yet blocked — hence real apps running both paths. We follow that.
+- **[OPEN / TRACKED] Out-of-region payments:** external payment for digital goods is a **rejection risk
+  outside the RU region** (App Store guideline 3.1.1). We need a mechanism to route/avoid so we do not get
+  rejected. Re-verify current policy at the payments implementation phase. Do not die on this hill; the
+  owner's real-world observation stands, but the risk is on record.
+- **[OPEN / TRACKED] Cross-platform spend compliance:** must not let web-funded (same-email) chips be
+  spent inside the iOS app (see §14 → I). A dedicated payments session will settle the iOS spend-
+  visibility. iOS v1 shows the packs but blocks Buy with a soft redirect to the web/Android build.
+
+---
+
+## 11. Gates
+
+- **[GATE] Apple Developer account** (in process). Development in the **Simulator is unblocked without it**.
+  It blocks, downstream: running on a **physical device**, enabling **Sign in with Apple** (needs an App ID
+  + capability), **push (APNs)**, **TestFlight / App Store release**. Sequence work so these land after the
+  account is active.
+
+---
+
+## 12. Audio — future (only if sounds are added) [FIXED intent]
+
+Two common anti-patterns we must **not** ship, both fixed via `AVAudioSession`:
+
+1. **Never silence the user's other audio.** Category **`.ambient`** (+ `.mixWithOthers`): mixes with the
+   user's music/podcast, does **not** interrupt it, and respects the **silent switch**. The typical mistake
+   is `.playback`, which stops others — we do not use it.
+2. **Never "capture" audio at launch.** Activate the audio session **lazily — only while actually playing a
+   sound** — and do not hold it active otherwise; never activate on boot. Avoids the "launched and muted my
+   music while playing nothing" annoyance.
+
+---
+
+## 13. Development sequence (the process, agreed)
+
+**Design the full online app up front; build in a vertical slice, then breadth.** Order:
+
+1. **Screen & moving-parts inventory** — enumerate every screen and, per screen, its states, data, and
+   reactions to actions (re-imagined for iOS, informed by the web functional domains but not mirroring
+   them). *(Next up — to be filled in below as we do step 1.)*
+2. **Navigation / state skeleton** — an app-level router; transitions expressed as state (`NavigationStack`
+   path, state-bound sheets), not bolted on afterward.
+3. **One vertical slice first — the game screen** (with stubs), fully interactive. This is where the
+   **design system** (tokens, SF typography, board/tile visual spec) and the **reusable component kit** are
+   born — on the highest-value screen, not on a login form.
+4. **Then breadth** — the remaining screens along the established patterns; each screen built with its
+   controls **and** mock data together (not screens-then-transitions-then-controls in horizontal passes —
+   SwiftUI is data-driven, so a screen and its controls co-evolve and transitions fall out of the state
+   model).
+
+Throughout: mock is an **architectural seam** (protocol + `DataMocks`), not throwaway — the real
+networking later slots in behind the same protocols. The **Swift engine port** is its own workstream
+(stub the game during the presentation phase; wire the real parity-pinned engine later).
+
+---
+
+## 14. Inventory — screens & moving parts (step 1)
+
+Seeded from `docs/FUNCTIONAL.md`, re-imagined for iOS-native idioms. Tags: **[keep]** as-is in
+spirit, **[re-imagine]** with a native idiom, **[deferred]** designed but delivered later. The
+per-screen **moving parts** (states / data / actions) are filled in section by section next, starting
+with the game screen (the vertical slice).
+
+### A. Boot / launch
+- **Loading splash** [keep] — crossword tiles (ЭРУДИТ / ЗАГРУЗКА / ОЖИДАНИЕ), minimal, aligned with the
+  fast-silent-boot principle (no empty flash).
+- **Offline first-launch → straight into the lobby as guest** [keep] (as Android).
+- **"Couldn't load" + Retry** [re-imagine] native, no web-sign-in fallback.
+- **"Client too old" update screen** [keep] native: Update (Store) / Play offline.
+
+### B. Onboarding
+- **Coachmark tours** (lobby series + game series) [re-imagine] via **TipKit**.
+
+### C. Auth / identity (v1: SIWA + email + guest)
+- **Login screen** [re-imagine] stacked buttons: **Sign in with Apple** (native sheet) + **Email** + **guest**.
+  VK / Telegram rows **[deferred]**.
+- **Email code entry** [keep].
+
+### D. Lobby
+- **"My games" list** [keep] — three sections (your turn / opponent / finished; empty hidden), ordering
+  rules, unread dots (red/amber), status-blink, swipe-to-remove finished, server games greyed-out offline.
+  Swipe/kebab → native **swipe actions**.
+- **Bottom tab bar** [re-imagine] → `TabView`: New Game / Statistics / Settings hub.
+
+### E. New Game
+- **New Game screen** [keep] — Quick game (AI / random), With friends (invite / pass-and-play), variant
+  pick (gated by preferences), RU "multiple words per turn" toggle, per-kind caps 🔒 prompts.
+- **Friend invite** [keep] — pick from friend list.
+- **Pass-and-play setup** [keep] — host PIN keypad, player rows (2–4), optional per-seat PIN.
+
+### F. Game — VERTICAL SLICE (step 3)
+- **Game board screen** [keep] — board on **`Canvas`**, rack, action bar (combined pass/exchange, hint,
+  shuffle, confirm), on-board legality preview + score badge, bag count.
+- **Scoreboard header / seats** [keep] — opponent cards with add-friend 🤝 / block ✖️.
+- **Move history** [keep].
+- **Comms screen** [keep] — 💬 chat / 🔎 dictionary tabs.
+- **Dictionary word-check** [keep] — complaint, external reference link (network-gated).
+- **Hint** [keep] — lays suggested tiles; vs_ai 🔒 idle-gate + countdown (steady in-app timer).
+- **Pass / exchange** [re-imagine] native sheet.
+- **Pass-and-play in game** [keep] — seat PIN unlock, leader controls (skip / remove / end early).
+- **Connection-lost banner + frozen play area** [keep].
+- **End-of-game + export** [keep] — GCG + PNG via the native **share sheet**.
+
+### G. Social / friends
+- **Friends screen** (Settings → Friends) [keep] — list, one-time code (issue / redeem), requests,
+  block / unblock / unfriend; kebab → native **context menu**.
+- **Incoming invitations** [keep] — accept / decline.
+
+### H. Profile & settings
+- **Settings hub** [re-imagine] grouped `List`: settings, profile, friends, wallet, about.
+- **Settings** [keep] — language, theme, board bonus-label style, reduce-motion, zoom-the-board,
+  notifications-in-app-only, block toggles.
+- **Profile** [keep] — display name, timezone, away window, variant preferences, sign-in methods
+  (link / unlink / merge), delete account; inline editing.
+- **Merge confirmation** (irreversible) [keep].
+- **Delete account** [keep] — mailed code / typed phrase.
+
+### I. Wallet & store (designed in v1, delivery staged)
+- **Wallet** [keep, deferred delivery] — balance (per-platform chips), Active line, Buy / Spend toggle,
+  watch-ad option, Exchange confirm, store-compliance warnings. Region/store-aware; ties to the §10
+  payment seam.
+
+### J. Feedback
+- **Feedback screen** [keep] — message + single attachment, reply display, feedback-banned state.
+
+### K. Info / legal
+- **About** [keep] — version, links.
+- **Legal docs** (EULA / privacy / offer) [re-imagine] — in-app viewer or Safari, not web pages.
+
+### L. Cross-cutting (not screens)
+- **Advertising banner** under the nav (free players) [keep] — component, campaign rotation / colours / urgent.
+- **Push (APNs)** + real-time in-app updates — data flows, not a screen (APNs is also the background
+  energy model, §5).
+
+### Excluded (web / platform-specific — not in the native iOS app)
+- **Admin console `/_gm`** — server-rendered web, not part of any client.
+- **Landing page** — web-only.
+- **Telegram / VK Mini App** hosting + their diagnostic screens — the iOS app is not a Mini App.
+- **PWA install CTA** — web-only.
+- **Promo bot**, **Telegram support chat** — Telegram-side (in-app Feedback in §J is kept).
+
+### Native idioms replacing web mechanics
+`TabView` (tab bar) · native swipe actions / context menus (swipe-remove, kebab) · sheets (popups/modals)
+· `ShareLink` / share sheet (export) · **TipKit** (coachmarks) · grouped `List` (settings/legal) · SIWA
+native sheet (auth).
+
+### Assets, tiles & icons [FIXED]
+- **Tiles are drawn as runtime vectors** (a rounded rect + a font glyph + the point value, on the board
+  `Canvas`) — **no image assets, no pre-generation, no local-store cache.** Resolution-independent (crisp
+  under zoom-on-drop), theme/variant/locale-adaptive for free. Cache rendered tile images
+  (`ImageRenderer`) **only if** profiling later shows a need. The crossword loading splash **reuses the
+  same tile component** (zero assets).
+- **LaunchScreen** is static, OS-level, a simple brand mark (background + logo/wordmark; system font or a
+  single logo image — **no tile assets**). Its duration **equals the real launch time** — it **cannot** be
+  extended or held programmatically (and fake delays are discouraged); the "longer" splash is the **in-app
+  crossword splash** (its timing is ours, shown until the lobby is ready). Match the LaunchScreen
+  background to the in-app splash so the OS→app handoff is seamless (no flash).
+- **Icons = SF Symbols** (the system icon set) everywhere — all the emoji in this plan are placeholders
+  for meaning; the real UI uses SF Symbols (gear, chart.bar, dice, bubble.left, shuffle, lightbulb,
+  person.badge.plus, xmark/hand.raised, square.and.arrow.up, lock, …). **Custom vectors only where no
+  system symbol fits:** the three variant emblems and the tiles.
+
+### Per-screen moving parts
+
+#### F. Game screen — detail
+
+**Layout [FIXED]**
+- **iPhone: full board always visible + zoom-on-drop** (hybrid, web-parity, setting-gated by the
+  existing "Zoom the board" toggle). Board scaled to width; on tile drop it magnifies toward the drop
+  point for precision.
+- **Bottom-anchored stack**, top→bottom: *(top strip — the ad banner (L) + connection chrome, else
+  empty)* → **seats header** → **board** → **rack** → **bottom toolbar**. Everything is packed to the
+  bottom; the top strip hosts the L banner / Connecting…/Offline/connection-lost chrome, else empty.
+- **Orientation [FIXED]: iPhone portrait-only; iPad portrait + landscape.**
+
+**Four regions**
+1. **Scoreboard / header** — seats (name, score, whose-turn), unread dot (red msg / amber nudge),
+   connectivity state ("Connecting…" / Offline chip / connection-lost banner), 💬 entry to history/comms.
+2. **Board (`Canvas`)** — 15×15 grid, placed tiles, staged tiles with on-board legality preview
+   (light green when a word forms, darker on run-through board tiles, pink when none; orange badge =
+   score), zoom-on-drop.
+3. **Rack** — player tiles, drag/tap to place, shuffle, in-rack reorder.
+4. **Action bar** — combined pass/exchange, hint (vs_ai 🔒 idle-gate + countdown), shuffle, confirm
+   (only when the move is legal), bag count.
+
+**State axes (repaint the screen)**
+- **Whose turn:** mine (preview + submit) vs opponent's (draft placement only, position-only).
+- **Phase:** waiting for opponent (auto-match "searching for opponent"; resign/chat/nudge off) →
+  active → finished.
+- **Connectivity:** online / connecting / offline / connection-lost-in-online-game (frozen).
+- **Kind:** vs_ai (honest 🤖: unlimited wallet-free hints idle-gated, no chat/nudge/add-friend, no
+  clock — 7-day only, no export) · auto-match 2p (possibly a disguised robot) · friend 2–4 ·
+  pass-and-play (seats, PINs, leader).
+- **Variant:** Erudite / RU Scrabble / EN Scrabble; RU "multiple words per turn" toggle changes the
+  preview (main word only vs all perpendiculars).
+
+**Interactions**
+- Place tile (drag or tap; the game infers direction) · **blank ('?') letter picker** · recall a
+  staged tile to the rack · legality preview on-device (first-time warm-up; server fallback) · confirm
+  (only when legal) · resign · shuffle · **hint** (per-game allowance → wallet; vs_ai unlimited but
+  idle-gated 30 min, 🔒 + steady in-app countdown) · zoom-on-drop (setting) · **per-game composition
+  persistence** (rack arrangement + uncommitted move restored, cross-device).
+
+**Sub-surfaces (from the header)**
+- **Seat cards** (with history open): add-friend 🤝 / block ✖️, confirm on a fading ✅; disabled/
+  disappear rules.
+- **Move history** (words, coordinates, scores; pass/exchange/resign/timeout notes; closing ± endgame
+  settlement).
+- **Comms** — chat (1 msg/turn, ≤60 chars, no links) + dictionary word-check (complaint, external
+  reference link); **nudge**.
+- **Pass-and-play** — seat PIN unlock (keypad replaces the locked seat's rack); leader button →
+  skip / remove / end-early (leader password); hints and chat off.
+- **End-of-game** — result, final scores (yours first), export 📤 (GCG + PNG, never for honest-AI);
+  "could not be continued → draw" organizer note.
+- **Connection-lost (online game)** — slim banner, play area freezes (rack + move controls disable;
+  resign/add-friend/block/chat hidden; a started move stays as a draft); if already in chat/dictionary
+  you stay (chat read-only, dictionary keeps checking on-device).
+
+**UX decisions [FIXED]**
+- **Comms sheet:** a **single detented sheet** with a segmented control **[History | Chat |
+  Dictionary]**; the board + seats header stay visible above; native swipe-to-dismiss + grabber.
+  **Opened by tapping the seats header** (where the unread dot / 💬 live). iPad landscape later adapts
+  it to a side column. (Simplifies the web's nested history → comms navigation.) The **export 📤**
+  lives inside this sheet (History segment, finished game) — **not** in the header.
+- **Bottom toolbar (not a TabBar).** The in-game controls are actions, so they sit in a native bottom
+  toolbar (`ToolbarItem(.bottomBar)`, the Safari/Mail pattern), **not** the app `TabView` — which is
+  navigation and is **hidden inside the game**. Layout: **`[pass/exchange] — [hint ⇄ confirm] —
+  [shuffle]`** (3 slots). The centre control **morphs hint → confirm** only once a legal move is
+  staged (doubles as "you can commit" feedback). **Exchange** is inside the `pass/exchange` control
+  (select tiles = exchange, none = pass). **Recall** a staged tile by tapping it — no dedicated button.
+- **Tile placement:** **both drag and tap-to-place**; recall by tap; the **blank ('?') letter picker**
+  is a popover over the variant's alphabet.
+- **Seat cards:** composed from primitives (`HStack`/`VStack` + design tokens, optional `GroupBox`),
+  no prebuilt control. Base header shows name / score / whose-turn / unread dot only.
+- **Opponent social actions:** **tap a seat card → a mini player panel** (popover on iPad, sheet on
+  iPhone) showing the relationship status (pending / friends / blocked) with **Add friend** / **Block**
+  (`Button(role: .destructive)` + native `confirmationDialog`). Replaces the web's in-place score-card
+  swap.
+- **Rack:** shuffle button; reorder tiles by in-rack drag; tap selects a tile for tap-place; freed
+  slots render empty.
+- **Waiting for opponent (auto-match):** the opponent card reads "searching for opponent" with a calm
+  activity indicator (not a blocking spinner); resign/chat/nudge hidden; you may arrange tiles if it is
+  your turn; a "you can close the app and come back" note.
+- **vs_ai hint-lock:** the hint control carries a 🔒 badge while idle-gated; a tap shows a transient
+  "unlocks in N min" popover; the lock lifts live at the mark.
+- **End-of-game:** a result plate on the board (win/lose/draw, final scores yours-first); export via the
+  sheet (above); never for honest-AI.
+- **Connection-lost / offline chrome** (per FUNCTIONAL, native styling): offline = blue header + Offline
+  chip; brief blip = quiet "Connecting…" in the header; connection-lost in an online game = slim banner
+  + frozen play area (rack/controls disabled, resign/social/chat hidden, started move kept as a draft).
+
+*(F inventory + UX skeleton complete. Design-system specifics — colours, typography, tile visuals —
+emerge while implementing the vertical slice, step 3.)*
+
+#### D. Lobby — detail
+
+**UX decisions [FIXED]**
+- **List style:** native **inset-grouped `List`** (the Settings-app look — floating rounded section
+  cards over a grouped background). Sections: **your turn / opponent's turn / finished** (empty hidden).
+- **Grouping (option A — unified lobby):** one lobby, all games in the three state sections. **Local
+  games** (offline vs_ai + pass-and-play, which never sync) are **badged inline** with an "on-device"
+  marker. When offline, **server rows grey out in place** (un-openable; a tap explains why) — not moved
+  or hidden.
+- **Fold/unfold:** **opponent + finished** sections are collapsible (`DisclosureGroup`); **"your turn"
+  is always expanded** (it is the action section). Fold state is remembered per-device.
+- **Bottom `TabView` (app navigation):** New Game / Statistics / Settings hub. (Confirmed: the TabBar
+  switches screens; in-game controls are a bottom toolbar, not this.)
+- **Row anatomy:** opponent name (or "searching for opponent" for an unfilled auto-match) · a **variant
+  emblem** (three distinct icons — Erudit / RU Scrabble / EN Scrabble; **not** a national flag, which
+  can't separate the two Russian variants) · unread dot (red msg / amber nudge) · an **on-device badge**
+  for local games · a **result** for finished games. **No status icon** (the sections already group by
+  status). No avatars (name only). Compact, line-separated. *(Exact visual TBD on the slice.)*
+
+**Behaviour (per FUNCTIONAL, kept)**
+- **Ordering:** your-turn first (longest-waiting on top); opponent + finished most-recent first; a game
+  with any unread floats to the top within your-turn/opponent (finished keeps its order).
+- **Live updates:** a listed game that becomes your-turn or finishes while the lobby is open
+  **flashes its row briefly** (the status-icon blink is retargeted to a row-level flash, since there is
+  no status icon); the game also moving into the *your turn* section is itself a signal. An opponent's-
+  turn change is silent, applied in place.
+- **Unread dot:** next to the game — **red** when an unread message waits, **amber** when only nudges.
+- **Remove finished:** native **swipe action** → ❌ (per-account, permanent, no undo). An AI game you
+  left (resign or 7-day lapse) auto-drops from *finished*; a normally-finished AI game stays until
+  removed; no other type auto-removes.
+- **Cold open:** loading splash (crossword tiles ЭРУДИТ/ЗАГРУЗКА/ОЖИДАНИЕ) until the list is ready — no
+  empty flash.
+- **Offline chrome:** blue header + Offline chip; Stats tab disabled; invitations hidden; server rows
+  greyed.
+
+#### E. New Game — detail
+
+**UX decisions [FIXED]**
+- **Structure:** a top **segmented `[Quick game | With friends]`** + a contextual **inset-grouped form**
+  below (consistent with the lobby aesthetic).
+  - *Quick game:* opponent segmented **`[AI | Random]`** → variant (emblem chips) → RU "multiple words"
+    toggle → **Start**.
+  - *With friends:* rows **Invite a friend** / **Pass-and-play** → pushed sub-flows.
+- **Variant picker:** **emblem chips / segmented** (≤3 variants); **hidden entirely when a single variant
+  is enabled** (the common default — Erudite only).
+
+**Behaviour (per FUNCTIONAL, kept)**
+- **Quick game:** AI default (instant 🤖, no wait) / Random (auto-match 2p — drops you into the game to
+  wait inside; "you can close the app and come back" note).
+- **With friends offline → only pass-and-play** (invite needs the network).
+- **RU "multiple words per turn":** default **off**; RU games only; English is always standard, no toggle.
+- **Per-kind caps** (AI / random / friend): a start at its cap shows **🔒**; a tap opens a prompt — a
+  **guest** is invited to sign in / create an account, a **signed-in** player is told to finish a current
+  game. **Accepting an incoming invitation is never capped.**
+- **Friend invite:** pick **2–4** from the friend list; the inviter sets the game settings; starts once
+  **all accept**; any decline cancels; an unanswered invite expires in **7 days**; shareable as a Telegram
+  deep link (on VK the link only opens the app, the code is entered by hand).
+- **Pass-and-play setup:** host PIN keypad → "are you playing too?" (yes → first seat takes your name) →
+  name players 2–4 (add/remove; a removal asks the leader password) → optional per-seat PIN.
+- **Per-game settings set** (inviter chooses for friend games; quick games use defaults): variant · RU
+  multiple-words · **move timeout** (5 min–24 h, default 24 h) · **hints** (allowed? how many each) ·
+  **leaver's-tile disposition** (returned to bag / removed — 3–4-player games only).
+
+**UX decisions [FIXED] (sub-details)**
+- **Cap 🔒 prompt:** a 🔒 badge on the **Start** control (looks unavailable); a tap opens a native
+  alert — guest: a "Sign in / Create account" action; signed-in: an informational "finish a current
+  game first."
+- **Pass-and-play setup** (pushed, stepped): (a) 4-digit host PIN on a custom lock-screen-style keypad
+  (no built-in iOS control — composed); (b) "are you playing too?"; (c) player rows as an editable
+  `List` (EditMode add/remove; a removal is gated by the leader password); (d) per-seat PIN via a small
+  lock toggle in the row.
+- **Friend-invite** (pushed): multi-select from the friends `List` (checkmarks, 2–4) → a **settings
+  step** reusing the per-game settings set → **Send** (+ shareable link). Setting controls: move
+  timeout = native picker (5 min–24 h); hints = toggle + stepper; leaver disposition = segmented
+  `[to bag | out of play]`.
+
+#### C. Login / identity — detail (v1: SIWA + email + guest)
+
+**UX decisions [FIXED]**
+- **No hard login wall — guest by default** (offline-first, as Android native). First launch drops
+  straight into the lobby as a guest.
+- **Reusable sign-in sheet:** a bottom **detented sheet** (same idiom as the comms sheet) with the
+  sign-in buttons in a **vertical stack** — **Sign in with Apple** (`SignInWithAppleButton`) + **Email**
+  (future VK/TG rows append here). **Shown once on first launch, dismissible** — dismiss = stays guest.
+  **Reused on demand** from the Profile "Sign in" action.
+- **Email flow:** address → **6-digit code** entry → signed in / linked; rate-limit feedback (cooldown +
+  hourly cap). **Code-only on native** — the magic link is unused (it opens an external browser that
+  can't return to the app; mirrors the installed-PWA case in FUNCTIONAL).
+- **SIWA:** native system sheet → gateway validates → create / link the account.
+- **Merge on collision** (the identity already belongs to another account): guest initiator = seamless;
+  durable initiator = irreversible confirmation. Triggered by sign-in; the merge screen itself lives in
+  **H** (Accounts, linking & merge).
+
+#### B. Onboarding — detail (TipKit, native)
+
+**UX decisions [FIXED]**
+- **TipKit, native flavour** (confirmed): contextual tips anchored to controls, ordered via **`TipGroup`**
+  — **no full-screen dimming, no tap-anywhere-advance**; each tip dismisses itself (its ✕ or performing
+  the action). Shown once; per-device eligibility.
+- **Two tours:** **lobby series** (⚙️ settings, ✏️ statistics, 🎲 new-game tabs) + **game series**
+  (scoreboard header, pass/exchange, hint, shuffle, rack). Localized (en/ru).
+- **First-launch sequence:** lobby (guest) → sign-in sheet (C) → on dismiss → the TipKit lobby tour
+  (so the sheet and the tips don't overlap).
+
+#### G. Friends — detail (Settings → Friends)
+
+**UX decisions [FIXED]**
+- **Structure:** a single **inset-grouped `List`** with sections **Requests** (incoming: accept /
+  decline; outgoing: cancel) · **Friends** · **Blocked** (unblock). A toolbar **"+"** opens the add
+  sheet.
+- **Add sheet ("+"):** **Enter a code** (6-digit redeem, valid 12 h) / **Share my code** (generate +
+  `ShareLink`).
+- **Friend-row actions:** **swipe actions** — **Remove** (destructive) + **Block** — each gated by a
+  naming **`confirmationDialog`** ("Remove from friends?" / "Block this player?").
+- Chat / nudge are **not** here — they live in the in-game comms sheet (F). Global block toggles
+  (incoming chat / friend requests) live in **Profile (H)**.
+
+**Behaviour (per FUNCTIONAL, kept)**
+- Two ways to friend: redeem a one-time code, or a request to someone you've played with
+  (accept / ignore→30-day lapse / decline→blocks until they hand you a code). Cancel your outgoing;
+  unfriend removes it.
+- A per-user block is one-directional and silent; **unblock and unfriend live only here**.
+
+#### H. Profile & settings — detail
+
+**UX decisions [FIXED]**
+- **Settings hub** = an icon **`List` of drill-down `NavigationLink` rows** (the Podcasts → Library
+  pattern), SF-symbol icons, with room left at the bottom for optional general info later. Rows:
+  - **Interface** (⚙️) → display-settings screen.
+  - **Friends** (person.2) → G.
+  - **Wallet** (creditcard) → I. **Hidden for guests.**
+  - **Info** (info.circle) → About + version + legal (K).
+  - **Feedback** → J. **Hidden for guests.** Unread-reply **badge** on the Settings tab **and** on this
+    row.
+- **Profile = a top-right nav-bar icon** (`ToolbarItem(.topBarTrailing)`, `person.circle`; filled /
+  initial when signed in) on the settings hub: **guest → the sign-in sheet (C); signed-in → the profile
+  screen.** (Duplicated onto the lobby only if asked later.)
+- **Interface screen** (display prefs): language · theme · board bonus-label style · reduce-motion ·
+  zoom-the-board.
+
+**Guest has no editable settings** [FIXED] — the random nick is not changeable, the variant is always
+`erudite_ru`, the timezone is auto-detected (never set by hand). So there is **no guest profile
+screen**: the profile icon for a guest opens the **sign-in sheet** (confirms C). It also confirms E's
+"variant picker hidden when a single variant is enabled" for guests.
+
+**Profile screen (signed-in / durable)** [FIXED] — an inset-grouped `Form`:
+- **Name** — inline `TextField` + validation (letters + `·`/`.`/`_` separator, optional trailing `.`
+  or ≤5 digits, ≤32 chars, ≤5 specials).
+- **Play** — timezone (UTC-offset picker, pre-filled from the device) · away window (10-min grid, ≤12 h,
+  wraps midnight; a two-time range) · variant preferences (multi-select emblems, ≥1 kept) ·
+  notifications-in-app-only (`Switch`, default on).
+- **Privacy** — global block toggles (incoming chat / friend requests).
+- **Sign-in methods** — rows link / unlink; **email is "changed", not unlinked**; the **last** method
+  can't be unlinked; a provider that belongs to another account offers the irreversible **merge** (guest
+  initiator seamless, durable initiator confirmed).
+- **Delete account** — destructive footer; confirm via a mailed code (email account) or a typed phrase.
+  Legal-retention removal (not erasure), per FUNCTIONAL.
+
+#### I. Wallet & store — detail (durable only; delivery staged)
+
+**UX decisions [FIXED]**
+- **Structure:** inset-grouped — a **balance card** (running-context «Фишка» first, then linked
+  other-platform chips behind their logos: VK / Telegram / web / **Apple** as a new context) → **Active**
+  line (hints remaining + ad-free end date / "forever"; hidden when empty) → segmented **`[Buy | Spend]`**
+  → rows. **No purchase history.**
+- **Buy (v1):** the chip packs are **shown** (the user sees purchases exist in the game), but tapping
+  **Buy** shows a light message — *"Purchases are unavailable on the Apple platform. You might like
+  another version of [our app](landing)."* — a soft redirect to the Android/PWA build while payments are
+  not wired. Chosen over hiding so the offering stays visible; unlocking real Buy later (IAP / external
+  rails) is then just enabling the path.
+- **Spend:** values (extra hints, days without ads) at a fixed chip price; **Exchange** action + a
+  confirm `confirmationDialog`.
+
+**[OPEN / TRACKED — a dedicated payments session, not resolved here]**
+- **Cross-platform spend compliance (Apple landmine):** we must **not** let a user buy chips on the web
+  (email login) and then **spend** them inside the iOS app where the same email is signed in — spending
+  externally-funded digital currency in-app violates App Store rules. This reshapes the iOS
+  **store-compliance spend-visibility** (what of the balance is spendable on iOS, given there is no
+  Apple-funded chip yet). The owner will settle it in a dedicated payments session. Ties to §10.
+
+#### J. Feedback — detail (durable only; guests hidden)
+
+**UX decisions [FIXED]**
+- inset-grouped `Form`: **`TextEditor`** (≤1024, live counter) → attachment row → **Send**.
+- **Attachment:** one file ≤1 MB (images / PDF / text-log / office / RTF / archives). **"Attach"** →
+  menu **`PhotosPicker` (Photos)** / **`fileImporter` (Files)**; **no camera**. An unsupported file is
+  refused **without naming** the allowed types; the chosen file shows as a removable chip.
+- **After send:** the form clears, "Ваше сообщение отправлено"; while the operator has not dealt with it,
+  a locked state "Ожидаем рассмотрения вашего последнего обращения" (Send disabled).
+- **Reply** below: "Ответ на ваше последнее сообщение"; links open in `SFSafariViewController`; marked
+  read on view; gone after a week.
+- **Unread-reply badge:** Settings tab + Feedback row (H).
+- **Feedback-barred** player: Send disabled.
+
+#### K. Info / legal — detail
+
+**UX decisions [FIXED]**
+- **About screen** (Info hub row): app name · **version** (native build + the client-version) · links to
+  the three legal docs · copyright; optional "Rate on the App Store".
+- **Legal docs** (EULA `/eula/`, privacy `/privacy/`, offer `/offer/` + live price list): open via
+  **`SFSafariViewController` to the hosted URLs** — always current, the offer's price list stays live,
+  bilingual handled by the page; no render pipeline duplicated in the app. **Offline:** unavailable
+  ("недоступно офлайн").
+
+#### A. Boot / launch & update — detail
+
+**UX decisions [FIXED]**
+- **LaunchScreen:** static, OS-level, instant (**iOS cannot animate the launch screen**) — brand/logo.
+- **In-app loading:** the crossword-tiles splash (ЭРУДИТ/ЗАГРУЗКА/ОЖИДАНИЕ) shows **only while the lobby
+  list isn't ready**; fast silent boot → usually straight to the lobby. Offline cold launch → straight to
+  the offline lobby.
+- **"Couldn't load" + Retry:** a native screen when an online launch can't reach the backend (a quiet
+  retry first).
+- **Client too old** (only on an online action, never while playing offline): full-screen, non-dismissable
+  — **Update** (App Store listing) + **Play offline** (keep on-device games).
+- **"Update available" (soft, not required):** a **transient top banner styled like a native
+  notification** — "Пора обновить приложение", **tap → App Store**, **auto-dismiss after 5 s**, shown on
+  **every launch when online**. (iOS has no first-party toast → a custom notification-style banner;
+  deviates by choice from the web's persistent dismissible bar.)
+
+#### L. Advertising banner — detail (cross-cutting component)
+
+**UX decisions [FIXED]**
+- **Placement:** a one-line strip **on the main tabs (Lobby / New Game / Statistics) AND in-game (F)** —
+  players spend most time in-game. Hidden in settings drill-downs and modal flows. **In-game it occupies
+  the top strip** (the empty space above the seats header), coexisting with the connection chrome
+  (Connecting… / Offline / connection-lost banner sit with it).
+- **Audience:** free players only (not lifetime-paid, no purchased hints, no `no_banner` role); guests
+  see it; appears/disappears **in place** on a property change.
+- **Language (native, no bot channel):** the **interface language** (RU default) — there is no "bot you
+  play through" here.
+- **Not hidden under TipKit** (no dimming overlay, unlike the web coachmarks).
+
+**Behaviour (per FUNCTIONAL, kept)**
+- Operator campaigns (weight %, optional window); compete in proportion to weight; a **house/default**
+  campaign fills the unsold share; an **urgent** campaign shows to everyone and is the only thing shown.
+- Fair weighted rotation; a multi-message campaign cycles in turn; transitions (fade-out → gap →
+  fade-in); long-message scroll; timings from the server (`/_gm/banners`).
+- Per-non-default-campaign colours (theme-aware set + optional dark override; derived border); urgent flag.