Local dev setup is way too painful

[shalgrim]

Problem

Getting the app running locally for simple frontend testing requires:

1. Docker (or local Postgres) for the database — no SQLite fallback
2. Backend running with correct .env configuration
3. Frontend running
4. API key configuration that's finicky (401s even after setting the key in the UI)

This is way too much friction for testing a CSS change.

Suggestions

• Add a SQLite fallback for local development so Docker/Postgres isn't required
• Fix the API key flow — currently easy to end up with persistent 401s after saving the key in Settings
• Consider a single make dev or npm run dev:all command that starts everything
• Add a frontend-only mock mode for testing UI changes without needing the full backend stack