initial: dungeon crawler with Bun + TypeScript modular architecture

- 19 TypeScript modules under src/ (constants, entities, room, game, render)
- Canvas 2D rendering with dark fantasy palette
- Room-based navigation, random 7x7 map generation
- Two combat modes: ranged (pistol) and melee (knife)
- Wall collision with door opening support
- Minimap, HP bar, enemy AI
- Bun build pipeline: src/main.ts -> dist/main.js + dist/index.html

src/main.ts

@@ -0,0 +1,32 @@
+import { setupInput, KEYS } from './input';
+import { Game } from './game/Game';
+
+// Global key bindings (mode toggle, restart) handled here
+setupInput();
+
+window.addEventListener('keydown', (e: KeyboardEvent) => {
+  const game = (window as any).__game as Game | undefined;
+  if (!game) return;
+
+  // Toggle combat mode
+  if ((e.key === 'Tab' || e.key === 'q' || e.key === 'Q') && !game.gameOver && !game.won) {
+    e.preventDefault();
+    game.toggleMode();
+  }
+
+  // Restart
+  if (e.key === 'r' || e.key === 'R') {
+    if (game.gameOver || game.won) game.restart();
+  }
+});
+
+// Bootstrap
+window.addEventListener('load', () => {
+  const canvas = document.getElementById('game') as HTMLCanvasElement;
+  if (!canvas) {
+    document.body.innerHTML = '<p style="color:red">Error: canvas element not found</p>';
+    return;
+  }
+  const game = new Game(canvas);
+  (window as any).__game = game;
+});