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

.gitignore

@@ -0,0 +1,37 @@
+# Dependencies
+node_modules/
+.pnpm-store/
+
+# Build output
+dist/
+*.tsbuildinfo
+
+# Turborepo
+.turbo/
+
+# Environment (secrets)
+.env.local
+.env.*.local
+
+# Tauri
+packages/app/src-tauri/target/
+
+# IDE
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Debug
+npm-debug.log*
+pnpm-debug.log*
+
+# Test coverage
+coverage/
+
+# Storybook
+storybook-static/