prepare app for public app store distribution

- rebrand from 습관 트래커 to 해빗랩 across templates, manifest, service worker
- add HTTPS redirect middleware for reverse-proxied deployments
- add public landing page (/) and privacy policy page with real data
  handling disclosures
- add in-app account deletion (Apple review requirement)
- add Android TWA Digital Asset Links support (/.well-known/assetlinks.json)
- add SFTP deployment script for the Synology-hosted server

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -2,6 +2,7 @@ __pycache__/
 *.pyc
 .env
 .env.dev
+deploy.env
 .venv/
 venv/
 *.egg-info/