Stage 17: UI defect fixes (russian variant, Telegram theme/nav/banner, reconnect, hint zoom, plaque, history, transitions, per-game cache)

- #6 align the UI variant id to the backend canonical 'russian_scrabble' (type, variants, Lobby, mock, tests) — fixes the New->Russian 400
- #11/#12 inside Telegram force the colour scheme from WebApp.colorScheme (over OS prefers-color-scheme, fixing the Telegram Desktop breakage) and hide the theme switcher
- #14/#15 nav bar takes Telegram's bg; announcement banner gets a dedicated subtle --ad-bg accent token
- #16 suppress the reconnect banner while backgrounded and silently reconnect the live stream on return to the foreground
- #17 hint zoom scrolls to the placement's bounding box, not the top-left
- #19/#20 players plaque: active seat raised with side shadows, others sunk; tap toggles history
- #21/#23 history: scrollbar-gutter:stable (no word jitter); fixed-height drawer pins the bottom shadow to the board
- #3 (UI) disable nudge on the player's own turn
- #18a directional screen slide transitions (forward in from the right, back reveals the lobby)
- #13 per-game in-memory cache: instant render on re-entry + background refresh
- e2e: openGame waits for the slide transition to settle

ui/src/lib/variants.ts

@@ -14,13 +14,13 @@ export interface VariantOption {
 // ALL_VARIANTS lists every variant in display order.
 export const ALL_VARIANTS: VariantOption[] = [
   { id: 'english', label: 'new.english' },
-  { id: 'russian', label: 'new.russian' },
+  { id: 'russian_scrabble', label: 'new.russian' },
   { id: 'erudit', label: 'new.erudit' },
 ];
 
 // VARIANT_LANGUAGE maps each variant to its game language. en -> English;
 // ru -> Russian + Эрудит.
-export const VARIANT_LANGUAGE: Record<Variant, 'en' | 'ru'> = { english: 'en', russian: 'ru', erudit: 'ru' };
+export const VARIANT_LANGUAGE: Record<Variant, 'en' | 'ru'> = { english: 'en', russian_scrabble: 'ru', erudit: 'ru' };
 
 // availableVariants gates ALL_VARIANTS by the session's supported languages. An empty
 // or absent set is ungated (a web/legacy session without a declared set), returning