Replace the checked-in styles.css with a build-time Tailwind CSS
pipeline. input.css defines CSS custom properties for light/dark
themes, mapped to Tailwind utilities via @theme. build.rs runs
the Tailwind CLI to generate styles.css at compile time.
Add dotenvy::dotenv() call before CLI argument parsing so that
environment variables (e.g. API keys) can be set in a .env file
instead of the shell environment. Add .env to .gitignore.
- Add BackupData struct and BackupService with raw SQL export/import
- Restore uses raw inserts to bypass brew deductions and timeline creation
- Restore requires an empty database, inserts in FK dependency order
- Add comprehensive e2e test verifying full round-trip fidelity
