Stage 7 (wip): UI shell, libs, mock transport, screens (lobby->game), e2e smoke

- plain Svelte 5 + TS + Vite (no SvelteKit); CSS-token design system (Telegram-ready), hash router, IndexedDB session
- pure libs: domain model, premium/value maps ported from solver, board replay, placement state machine, i18n en/ru
- in-memory mock transport + seed data; pnpm start runs lobby->active game->board with no backend
- board: pointer-drag + tap placement, MakeMove (popup / 1s-hold commit), two-state zoom, blank chooser, exchange, hint, word-check, chat
- Playwright smoke (mock) green; svelte-check clean; mock bundle ~37 KB gzip

ui/src/vite-env.d.ts

@@ -0,0 +1,11 @@
+/// <reference types="svelte" />
+/// <reference types="vite/client" />
+
+interface ImportMetaEnv {
+  /** Base URL of the gateway Connect endpoint. Empty in dev (same-origin proxy). */
+  readonly VITE_GATEWAY_URL?: string;
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv;
+}