Initial commit: Arcanum TD — medieval fantasy tower defense

Vite + React + PixiJS + TypeScript. Features:
- 4-level campaign (King's Road → Obsidian Keep)
- Isometric 2.5D grid with ley-line mechanics
- ECS architecture (entities, components, systems)
- 4 tower types, hero spellcaster, 10+ enemy types
- Lich King boss with 3-phase AI
- Meta-progression: essence, rune unlocks
- Full UI redesign with fantasy design system

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?