feat: implement Phase 30 - useGameStatus hook

Extract game status logic into dedicated hook following vim-maze pattern:

New Module Structure:
- src/useGameStatus/types.ts: GameStatus and GameStatusManager types
- src/useGameStatus/useGameStatus.ts: Hook implementation
- src/useGameStatus/index.ts: Public exports

Hook Implementation:
- State machine with 5 states (waiting/started/paused/game-over/game-won)
- Methods: startGame, togglePause, quitGame, setGameStatus
- Clean state transitions with useState
- Simpler than vim-maze (no intermediate 'has-key' state)

Updated Core Files:
- src/useGame.ts: Use useGameStatus() instead of inline useState
  - Compose gameStatusManager into GameManager
  - Cleaner separation of concerns

- src/types.ts: Import and re-export GameStatus types
  - GameManager extends GameStatusManager (intersection type)
  - Single source of truth for status types

- src/index.ts: Export useGameStatus hook publicly

Benefits:
- Reusable state machine
- Easier to test in isolation
- Follows unified API architecture
- Matches vim-maze patterns

State Transitions:
waiting → startGame() → started ↔ togglePause() ↔ paused
started → (win/lose) → game-won/game-over
* → quitGame() → waiting

Phase 30 complete. Next: Phase 40 (useCursor composition).

src/useGameStatus/index.ts

@@ -0,0 +1,2 @@
+export { useGameStatus } from './useGameStatus';
+export type { GameStatus, GameStatusManager } from './types';

src/useGameStatus/types.ts

@@ -0,0 +1,9 @@
+export type GameStatus = 'waiting' | 'started' | 'paused' | 'game-over' | 'game-won';
+
+export type GameStatusManager = {
+  gameStatus: GameStatus;
+  setGameStatus: (status: GameStatus) => void;
+  startGame: () => void;
+  togglePause: (pause?: boolean) => void;
+  quitGame: () => void;
+};

src/useGameStatus/useGameStatus.ts

@@ -0,0 +1,30 @@
+import { useState } from 'react';
+import type { GameStatus } from './types';
+
+export function useGameStatus() {
+  const [gameStatus, setGameStatus] = useState<GameStatus>('waiting');
+
+  function startGame() {
+    setGameStatus('started');
+  }
+
+  function togglePause(pause?: boolean) {
+    if (typeof pause === 'boolean') {
+      setGameStatus(pause ? 'paused' : 'started');
+    } else {
+      setGameStatus(prevStatus => prevStatus === 'paused' ? 'started' : 'paused');
+    }
+  }
+
+  function quitGame() {
+    setGameStatus('waiting');
+  }
+
+  return {
+    gameStatus,
+    setGameStatus,
+    startGame,
+    togglePause,
+    quitGame,
+  };
+}