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

packages/app/src/styles/main.css

@@ -0,0 +1,34 @@
+@import "tailwindcss";
+
+@theme {
+  --color-primary: #606060;
+  --color-primary-light: #808080;
+  --color-primary-dark: #404040;
+
+  --color-accent: #F7931A;
+  --color-accent-hover: #E88410;
+
+  --color-success: #10B981;
+  --color-error: #EF4444;
+  --color-warning: #F59E0B;
+  --color-info: #3B82F6;
+
+  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
+  --font-mono: 'Menlo', 'Monaco', 'Courier New', monospace;
+}
+
+html {
+  -webkit-tap-highlight-color: transparent;
+}
+
+body {
+  overscroll-behavior: none;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  * {
+    animation-duration: 0.01ms !important;
+    animation-iteration-count: 1 !important;
+    transition-duration: 0.01ms !important;
+  }
+}