Sign panel sessions and isolate test runs

- Replace in-memory auth sessions with signed cookies and signed OAuth state
- Add auth route coverage and update panel/web server wiring
- Switch test script to per-file Bun processes and clean up type checks

shared/games/chess/chess.plugin.ts

@@ -43,10 +43,12 @@ export const chessPlugin: GamePlugin<ChessState, ChessAction> = {
     createInitialState(players: string[], options?: Record<string, unknown>): ChessState {
         const game = new Chess();
         const timeControlKey = (options?.timeControl as string) ?? "blitz_5_3";
-        const tc = TIME_CONTROLS[timeControlKey] ?? TIME_CONTROLS.blitz_5_3;
+        const tc = TIME_CONTROLS[timeControlKey] ?? TIME_CONTROLS["blitz_5_3"]!;
 
         // Randomly assign colors
-        const shuffled = Math.random() < 0.5 ? [players[0], players[1]] : [players[1], players[0]];
+        const shuffled: [string, string] = Math.random() < 0.5
+            ? [players[0]!, players[1]!]
+            : [players[1]!, players[0]!];
 
         const clock: ChessClock | null = tc.time > 0
             ? { white: tc.time, black: tc.time, increment: tc.increment, lastMoveAt: Date.now() }
@@ -108,7 +110,7 @@ export const chessPlugin: GamePlugin<ChessState, ChessAction> = {
                 const moveEntry = {
                     from: action.from,
                     to: action.to,
-                    san: game.history().slice(-1)[0],
+                    san: game.history().slice(-1)[0]!,
                     color: turn === "white" ? "w" as const : "b" as const,
                 };