chore(init): scaffold OpenFrame — Next.js + Bun + shadcn

Initialize OpenFrame project with core scaffold and UI foundation.

- Project scaffold: Next.js 16.1 (App Router) + Bun runtime
- UI: shadcn/ui + TailwindCSS; landing, dashboard, project, and auth UIs
- Video support: provider abstraction (YouTube first), video player page with timestamped comments and custom timeline
- Auth & DB: NextAuth skeleton and Prisma schema (Postgres) included
- UX: dark-mode toggle, full-width layouts, comments sidebar, video route moved to /watch/[videoId]
- Dev: added YouTube iframe integration, custom controls, and TypeScript types
- Next steps: DB migrations, API routes (CRUD), real data wiring, voice-recording & sharing

components/layout/index.ts

@@ -0,0 +1 @@
+export { Header } from './header';