Stage 7 (wip): docs bake + stage renumber (insert UI Stage 8, shift +1)

- PLAN.md: new Stage 8 (UI social/account/history); Telegram->9, Admin->10, Linking->11, Polish->12; tracker + Stage 7 refinements; split the Stage 6 'wired in Stage 7' note between 7 and 8
- ARCHITECTURE: promote ui to current (slice scope, board-replay, codegen, theming, mock)
- FUNCTIONAL(+ru): client-app section with the Stage 7/8 split
- README + ui/README + CLAUDE.md: UI build/run/test, codegen, pnpm notes
- bumped Stage 8-11 refs (+1) across docs and code comments

README.md

@@ -11,8 +11,9 @@ supports English Scrabble, Russian Scrabble and Эрудит.
   admin surface behind Basic Auth. *(added in a later stage)*
 - **`backend`** — internal-only service that owns every domain concern and
   embeds the [`scrabble-solver`](../scrabble-solver) engine library in-process.
-- **`ui`** — pure-HTML5 client (plain Svelte + Vite), embeddable in platform
-  webviews and packageable to native via Capacitor. *(added in a later stage)*
+- **`ui`** — pure-HTML5 client (plain Svelte 5 + TypeScript + Vite) over Connect-RPC
+  + FlatBuffers, embeddable in platform webviews and packageable to native via
+  Capacitor. See [`ui/README.md`](ui/README.md).
 - **`platform/*`** — per-platform side-services (e.g. the Telegram bot).
   *(added in a later stage)*
 
@@ -67,3 +68,15 @@ Key environment: `BACKEND_HTTP_ADDR` (default `:8080`), `BACKEND_LOG_LEVEL`
 (`debug|info|warn|error`, default `info`), `BACKEND_POSTGRES_DSN` (**required**).
 The full configuration surface and the go-jet regeneration step live in
 [`backend/README.md`](backend/README.md).
+
+## Run the UI locally
+
+```sh
+cd ui && pnpm install
+pnpm start     # mock mode: lobby -> game with no backend, on http://localhost:5173
+pnpm dev       # against a running gateway (Vite proxies the RPC path to :8081)
+```
+
+`pnpm check` (type-check), `pnpm test:unit` (Vitest), `pnpm test:e2e` (Playwright
+smoke vs the mock), `pnpm build` (static bundle). Details — including the committed
+edge codegen (`pnpm codegen`) — are in [`ui/README.md`](ui/README.md).