feat: initialize AIUI monorepo with project rules and core types

Foundation for the next-generation AI content surface UI:
- 16 Cursor rules files covering philosophy, Vue conventions, design system,
  content surfaces, plugin system, AI integration, renderers, security,
  Bitcoin-only policy, dev/prod modes, accessibility, performance, animation,
  mobile UX, and git workflow
- pnpm workspaces + Turborepo monorepo (@aiui/core, @aiui/app)
- Vue 3 + Vite + TypeScript + Tailwind CSS 4
- Core type system: plugins, renderers, messages, content blocks
- Plugin registry with renderer registration
- 50 mock film fixtures with search/filter utilities
- App shell with chat page layout
- Environment config templates

Made-with: Cursor

.env.example

@@ -0,0 +1,15 @@
+# AIUI Development Environment
+# Copy this file to .env.local and fill in your values
+
+# AI Provider (OpenRouter - gives access to many models including free ones)
+# Get your key at: https://openrouter.ai/keys
+VITE_OPENROUTER_API_KEY=sk-or-your-key-here
+
+# TMDB API (free, for real film poster images)
+# Get your key at: https://www.themoviedb.org/settings/api
+VITE_TMDB_API_KEY=your-tmdb-key-here
+
+# Development flags
+VITE_DEV_MODE=true
+VITE_MOCK_MEDIA_SOURCES=true
+VITE_DISABLE_CRYPTO=true