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

README.md

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+# Dungeon Crawl — Ranged / Melee
+
+A dark fantasy dungeon crawler inspired by *The Binding of Isaac*.
+Built with TypeScript and Canvas 2D, bundled with **Bun**.
+
+## Quick Start
+
+```bash
+bun install        # install deps (none currently required)
+bun start          # build + prepare dist/
+open dist/index.html
+```
+
+Or for development with watch mode:
+
+```bash
+bun run dev        # watches src/ and rebuilds dist/main.js
+# then open dist/index.html manually
+```
+
+## Controls
+
+| Key | Action |
+|---|---|
+| WASD | Move |
+| Arrow keys | Attack in direction |
+| Space | Attack in facing direction |
+| Tab / Q | Switch weapon (Ranged ↔ Melee) |
+| R | Restart (on Game Over / Victory) |
+
+## Weapons
+
+| Mode | Weapon | Speed | Damage | Effect |
+|---|---|---|---|---|
+| Ranged | Pistol | Fast (10cd) | 1 per shot | Ranged projectiles |
+| Melee | Knife | Slow (22cd) | 2 + knockback | Wide swing arc |
+
+## Room Types
+
+| Type | Description |
+|---|---|
+| Spawn | Starting room, no enemies |
+| Normal | 2–4 enemies |
+| Treasure | No enemies, loot room |
+| Boss | 1 boss enemy, clearing wins the game |
+
+## Project Structure
+
+```
+src/
+├── main.ts              Entry point
+├── constants.ts         Grid, canvas, tile/door constants
+├── types.ts             Shared TypeScript types
+├── math.ts              Utility: shuffle, rand, dist, overlap
+├── input.ts             Keyboard state (global KEYS map)
+├── doors.ts             Door geometry helpers
+├── room/
+│   ├── Room.ts          Room class (tiles, enemies, tears)
+│   ├── RoomMap.ts       Map generation (connected 7×7 grid)
+│   └── tiles.ts         Tile builders (wall/floor/door placement)
+├── entities/
+│   ├── Player.ts        Player stat block
+│   ├── Enemy.ts         Enemy stat block + enemy type logic
+│   ├── Tear.ts          Ranged projectile
+│   └── MeleeSwing.ts    Melee hitbox
+├── game/
+│   ├── Game.ts          Main orchestrator (loop, tick, render)
+│   ├── collision.ts     Wall collision (isBlocked, collidesWall)
+│   ├── transitions.ts   Room transition detection
+│   └── spawner.ts       Enemy placement logic
+└── render/
+    ├── roomRenderer.ts      Tile rendering
+    ├── entityRenderer.ts    Player, enemy, tear, melee drawing
+    ├── hudRenderer.ts       HP bar, mode indicator, HUD
+    └── minimapRenderer.ts   Minimap drawing
+```
+
+## Build System
+
+- **Bun** — runtime + bundler
+- `bun build` — bundles `src/main.ts` → `dist/main.js`
+- `build.ts` — production build with minification + HTML copy
+- No external libraries required (pure Canvas 2D)
+
+## Architecture
+
+- **Game** owns the game loop (`requestAnimationFrame`), the world
+  (`RoomMap`, `Player`), and dispatches to render functions.
+- **Tick** processes input → movement → attack → enemy AI → room
+  clear check → transitions → win condition.
+- **Transitions** check player tile position + keypress against door
+  geometry; call `Game.enterRoom()` which resets room state.
+- **Collision** allows bounding-box overlap at door openings (row/col
+  outside normal bounds).
+- **Rendering** is split into 4 pure functions that receive `ctx` + data.