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/blackjack/blackjack.plugin.test.ts

@@ -22,7 +22,7 @@ function blackjackHand(cards: Card[]): PlayerHand {
 }
 
 function makeSeat(hands: PlayerHand[], activeHandIndex = 0, hasBet = true): PlayerSeat {
-    return { hands, activeHandIndex, hasBet };
+    return { hands, activeHandIndex, hasBet, cumulativePnl: 0 };
 }
 
 /** Create a rigged state for deterministic testing. */