Bolt — Character counter with per-platform limits

Build Character counter with per-platform limits.

Stack: Next.js 15 App Router, TypeScript, Tailwind + shadcn/ui. Use SQLite (better-sqlite3) for any server-side storage so the app is self-contained.

Feature list:
- Full CRUD where applicable with optimistic UI.
- Empty states, loading states, error states.
- Mobile-responsive.
- Keyboard shortcuts for power users.
- Import/export in a sensible format (JSON or CSV).

Deliverables:
- Working app rendered in Bolt preview.
- Seeded demo data so it's useful on first load.
- A short README explaining any env vars and how to deploy.

If time-constrained, ship the happy path end-to-end before polishing.