feat(manavoxel): scaffold 2D pixel platform MVP (Phase 0)

Add ManaVoxel — a 2D top-down pixel platform for creating and programming
miniature worlds in the browser. This commit includes:

- SvelteKit + PixiJS 8 web app with chunk-based tilemap renderer
- Game engine: camera (scroll/zoom), input (keyboard/mouse/touch), player with
  AABB collision, editor/play mode toggle
- Pixel editor tools: brush, eraser, flood fill, pipette, box fill, line
  (Bresenham), undo/redo stack
- Shared types package: materials, areas, items, network protocol, inventory
- Demo world generator with terrain, buildings, trees
- Material palette UI with 15 materials, keyboard shortcuts
- Comprehensive design documents (Roblox analysis, tech stack options,
  voxel resolution analysis, 2D alternative comparison, full project plan)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/manavoxel/package.json

@@ -0,0 +1,14 @@
+{
+	"name": "manavoxel",
+	"version": "1.0.0",
+	"private": true,
+	"description": "ManaVoxel - 2D Pixel Platform for creating and programming miniature worlds",
+	"scripts": {
+		"dev": "pnpm run --filter=@manavoxel/* --parallel dev",
+		"dev:web": "pnpm --filter @manavoxel/web dev"
+	},
+	"devDependencies": {
+		"typescript": "^5.9.3"
+	},
+	"packageManager": "pnpm@9.15.0"
+}