feat: migrate app to sqlite and add bare-metal VPS ops

[rrvsh]

Summary

• migrate the runtime database layer from SQLx Postgres to SQLx SQLite, including settings/bootstrap paths, handler query bindings, and SQLite-compatible migration DDL
• remove docker- and Cloud Run-oriented repo wiring, replacing CI with Rust checks and simplifying local/dev defaults for a bare-metal target
• add deploy-ready VPS assets under ops/vps/ (systemd service, nginx site template, env template, bootstrap script, deploy script, and end-to-end rollout docs)

Validation

• cargo fmt
• cargo clippy --fix --allow-dirty
• cargo build
• cargo test

VPS rollout instructions

1. Clone the repo to /opt/aenyrathia/current on the VPS.
2. Run sudo ./ops/vps/bootstrap.sh.
3. Edit /etc/nginx/sites-available/aenyrathia and set server_name to your domain.
4. Edit /etc/aenyrathia/aenyrathia.env:
   • set DATABASE_URL (default is sqlite:///var/lib/aenyrathia/app.db)
   • set GIT_REMOTE, PB_LOG, and any custom sync interval
5. Add SSH credentials for git sync as aenyrathia user:
   • /home/aenyrathia/.ssh/id_ed25519
   • /home/aenyrathia/.ssh/known_hosts
   • permissions: 700 for .ssh, 600 for files
6. Validate and reload nginx:
   • sudo nginx -t
   • sudo systemctl reload nginx
7. Issue TLS cert:
   • sudo certbot --nginx -d <your-domain>
8. Build and restart app:
   • sudo ./ops/vps/deploy.sh
9. Point DNS A/AAAA to the VPS IP and verify login/edit/save/git-sync flows.

Notes

• this removes Postgres and Docker from runtime expectations for this service
• SQLite WAL mode and connection busy timeout are enabled in startup options