feat(games): refactor blackjack for continuous play, split/double, and table UI

Transform blackjack from single-round to continuous-play table sessions with
round lifecycle (betting → playing → resolved → betting), split/double down
actions, per-hand bet tracking, leave/join table mid-session, and a responsive
felt-style table UI with arc-positioned player seats.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

panel/src/lib/useGameRoom.ts

@@ -7,6 +7,10 @@ interface PlayerInfo {
     username: string;
 }
 
+interface RoundResult {
+    payouts: Record<string, { net: number }>;
+}
+
 interface GameRoomState {
     gameState: unknown;
     players: PlayerInfo[];
@@ -14,6 +18,7 @@ interface GameRoomState {
     roomStatus: "connecting" | "waiting" | "playing" | "finished" | "not_found";
     isSpectator: boolean;
     gameOver: { winner: string | null; reason: string; payout?: { amount: number; refunded?: boolean } } | null;
+    roundResult: RoundResult | null;
     error: string | null;
     sessionReplaced: boolean;
     roomOptions: { betAmount?: number };
@@ -36,6 +41,7 @@ export function useGameRoom(roomId: string, userId: string, role?: string, prefe
         roomStatus: "connecting",
         isSpectator: false,
         gameOver: null,
+        roundResult: null,
         error: null,
         sessionReplaced: false,
         roomOptions: {},
@@ -64,11 +70,17 @@ export function useGameRoom(roomId: string, userId: string, role?: string, prefe
 
                 case "GAME_STATE":
                     // Authoritative player view — sent directly to this player
-                    setState(prev => ({
-                        ...prev,
-                        gameState: msg.state,
-                        roomStatus: prev.roomStatus === "finished" ? "finished" : "playing",
-                    }));
+                    setState(prev => {
+                        // Clear round result when a new betting phase starts
+                        const phase = (msg.state as any)?.phase;
+                        const roundResult = phase === "betting" ? null : prev.roundResult;
+                        return {
+                            ...prev,
+                            gameState: msg.state,
+                            roundResult,
+                            roomStatus: prev.roomStatus === "finished" ? "finished" : "playing",
+                        };
+                    });
                     break;
 
                 case "GAME_STARTED":
@@ -116,6 +128,13 @@ export function useGameRoom(roomId: string, userId: string, role?: string, prefe
                     }));
                     break;
 
+                case "ROUND_SETTLED":
+                    setState(prev => ({
+                        ...prev,
+                        roundResult: { payouts: msg.payouts },
+                    }));
+                    break;
+
                 case "GAME_ENDED":
                     setState(prev => ({
                         ...prev,