Stage 17 round 6 (cluster 1): profile, tap flash, variant naming, chat/nudge by turn

- Profile: drop the hint-balance line.
- Board: no mobile tap flash on a cell tap (-webkit-tap-highlight-color: transparent),
  matching the web click; the only intentional cell animation stays the last-word flash.
- Variant names keyed by the game's alphabet, not the UI language: english -> Scrabble
  always, russian_scrabble -> Скрэббл always (unlocalized, never collide), erudit localized.
- Chat/nudge are mutually exclusive by turn: the message field + Send show on your turn,
  the nudge replaces them on the opponent's turn; while the nudge cooldown is active the
  button is disabled with a grey 'awaiting reply' caption to its left.

ui/src/lib/variants.ts

@@ -11,10 +11,11 @@ export interface VariantOption {
   label: MessageKey;
 }
 
-// ALL_VARIANTS lists every variant in display order. The labels are display names, not
-// language names: both Scrabble variants render as "Scrabble"/"Скрэббл" and Erudit as
-// "Erudite"/"Эрудит" (Stage 17) — the offered list is language-gated, so within one
-// language the names stay distinct.
+// ALL_VARIANTS lists every variant in display order. The labels are display names keyed by
+// the game's alphabet, not the interface language: the English-alphabet game is always
+// "Scrabble" and the Russian-alphabet Scrabble always "Скрэббл" (both unlocalized, so the
+// two never collide whatever the UI language); Erudit is localized "Erudite"/"Эрудит"
+// (Stage 17).
 export const ALL_VARIANTS: VariantOption[] = [
   { id: 'english', label: 'new.english' },
   { id: 'russian_scrabble', label: 'new.russian' },