fix(games): fix chess piece interaction and solo mode

Two bugs fixed:
- Piece <img> elements were intercepting pointer events, preventing
  dnd-kit drag handlers and square click handlers from firing. Added
  pointerEvents: "none" so events pass through to the board framework.
- Solo test mode (fillRoom with duplicate player IDs) always resolved
  to "white" in colorOfPlayer, making black moves impossible. Now
  detects duplicate IDs and returns the current turn's color instead.

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

panel/src/games/chess/ChessGame.tsx

@@ -17,7 +17,13 @@ const chessPieces: PieceRenderObject = Object.fromEntries(
             <img
                 src={`/pieces/${key}.svg`}
                 alt={key}
-                style={{ width: "100%", height: "100%", ...props?.svgStyle }}
+                style={{
+                    width: "100%",
+                    height: "100%",
+                    pointerEvents: "none",  // let events pass through to dnd-kit / Square handlers
+                    userSelect: "none",
+                    ...props?.svgStyle,
+                }}
                 draggable={false}
             />
         ),
@@ -149,7 +155,9 @@ export function ChessGame({ state, myPlayerId, isSpectator, onAction, players }:
     const view = state as PlayerView | SpectatorView;
     const playerView = isPlayerView(state) ? state as PlayerView : null;
     const myColor = playerView?.myColor ?? "white";
-    const boardOrientation = isSpectator ? "white" : myColor;
+    // Solo mode: both players are the same user — myColor flips each turn, so lock orientation to white
+    const isSoloMode = !isSpectator && players.length === 2 && players[0]?.discordId === players[1]?.discordId;
+    const boardOrientation = isSpectator || isSoloMode ? "white" : myColor;
     const isMyTurn = playerView ? view.turn === playerView.myColor : false;
     const isGameOver = view.result !== null;
     const moveHistoryRef = useRef<HTMLDivElement>(null);