feat(stats): best-move word, moves & hint-share, and a hint-count fix (#81)

The statistics screen gains real depth, plus a hint-count bug fix found along the way.

- Best move per variant: the screen shows the actual best-move word (drawn as game
  tiles; a wildcard shows its letter but no value), broken down by game variant, empty
  variants omitted. New account_best_move table, written at game finish.
- Moves & hint share: two new lifetime tiles — the player's play count and the share of
  plays that used a hint — from summed account_stats counters (moves, hints_used).
  Honest-AI games are excluded, like the rest of the stats.
- Hint-count fix: the in-game hint badge no longer goes stale across games. The global
  wallet now rides the wire apart from the per-game allowance (wallet_balance on
  StateView/HintResult/StatsView), so the client reads the live wallet rather than a
  per-game snapshot; game_players.hints_used now counts every hint (allowance + wallet),
  its true per-game total.
- Account merge: sums the new moves/hints_used counters and merges the per-variant best
  moves (higher score kept), which it previously dropped.
- Admin: the user card shows Moves and Hints used.
- UI polish: tab/label wording, game-over text, and e2e selectors hardened against label
  changes.

All wire additions are trailing (backward-compatible). Docs (ARCHITECTURE, FUNCTIONAL +ru,
UISN_DESIGN) updated in step.

ui/src/lib/codec.ts

@@ -11,6 +11,8 @@ import type {
   AccountRef,
   Banner,
   BannerCampaign,
+  BestMove,
+  BestMoveTile,
   BlockStatus,
   ChatMessage,
   EvalResult,
@@ -381,6 +383,7 @@ function decodeStateViewTable(v: fb.StateView): StateView {
     rack,
     bagLen: v.bagLen(),
     hintsRemaining: v.hintsRemaining(),
+    walletBalance: v.walletBalance(),
   };
 }
 
@@ -407,7 +410,7 @@ export function decodeMoveResult(buf: Uint8Array): MoveResult {
 export function decodeHintResult(buf: Uint8Array): HintResult {
   const r = fb.HintResult.getRootAsHintResult(new ByteBuffer(buf));
   const m = r.move();
-  return { move: m ? decodeMove(m) : emptyMove(), hintsRemaining: r.hintsRemaining() };
+  return { move: m ? decodeMove(m) : emptyMove(), hintsRemaining: r.hintsRemaining(), walletBalance: r.walletBalance() };
 }
 
 export function decodeEvalResult(buf: Uint8Array): EvalResult {
@@ -742,12 +745,26 @@ export function decodeRedeemResult(buf: Uint8Array): AccountRef {
 
 export function decodeStats(buf: Uint8Array): Stats {
   const v = fb.StatsView.getRootAsStatsView(new ByteBuffer(buf));
+  const bestMoves: BestMove[] = [];
+  for (let i = 0; i < v.bestMovesLength(); i++) {
+    const m = v.bestMoves(i);
+    if (!m) continue;
+    const word: BestMoveTile[] = [];
+    for (let j = 0; j < m.wordLength(); j++) {
+      const t = m.word(j);
+      if (t) word.push({ letter: s(t.letter()), value: t.value(), blank: t.blank() });
+    }
+    bestMoves.push({ variant: s(m.variant()) as Variant, score: m.score(), word });
+  }
   return {
     wins: v.wins(),
     losses: v.losses(),
     draws: v.draws(),
     maxGamePoints: v.maxGamePoints(),
     maxWordPoints: v.maxWordPoints(),
+    moves: v.moves(),
+    hintsUsed: v.hintsUsed(),
+    bestMoves,
   };
 }