feat(P5B.T3): useGame hook with realtime + makeMove

apps/desktop/src/hooks/useGame.ts

@@ -0,0 +1,75 @@
+import { useCallback, useEffect, useState } from 'react';
+
+import { getGame, makeGameMove, type GameRecord } from '@chat-app/shared/chat';
+
+import { supabase } from '../lib/supabase';
+
+export function useGame(gameId: string | null): {
+  game: GameRecord | null;
+  loading: boolean;
+  error: string | null;
+  makeMove: (move: object) => Promise<void>;
+} {
+  const [game, setGame] = useState<GameRecord | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!gameId) {
+      setGame(null);
+      setLoading(false);
+      setError(null);
+      return;
+    }
+    let cancelled = false;
+    void (async () => {
+      try {
+        setLoading(true);
+        setError(null);
+        const fresh = await getGame(supabase, gameId);
+        if (!cancelled) {
+          setGame(fresh);
+          setLoading(false);
+        }
+      } catch (err) {
+        if (!cancelled) {
+          setLoading(false);
+          setError(err instanceof Error ? err.message : 'failed to load game');
+        }
+      }
+    })();
+    const channel = supabase
+      .channel('game:' + gameId)
+      .on(
+        'postgres_changes',
+        {
+          event: 'UPDATE',
+          schema: 'public',
+          table: 'conversation_games',
+          filter: 'id=eq.' + gameId,
+        },
+        () => {
+          void getGame(supabase, gameId)
+            .then((fresh) => { if (fresh) setGame(fresh); })
+            .catch((err) => { console.warn('game realtime refetch failed', err); });
+        },
+      )
+      .subscribe();
+    return () => {
+      cancelled = true;
+      void supabase.removeChannel(channel);
+    };
+  }, [gameId]);
+
+  const makeMove = useCallback(async (move: object) => {
+    if (!gameId) return;
+    try {
+      await makeGameMove(supabase, { gameId, move });
+    } catch (err) {
+      setError(err instanceof Error ? err.message : 'move failed');
+      throw err;
+    }
+  }, [gameId]);
+
+  return { game, loading, error, makeMove };
+}