Add local-first SPA architecture and containerized production deploy.

Move data access to use-cases and IndexedDB repositories with optional
remote fallback, changelog/sync ports, and encrypted local backup.
Add production Docker Compose (nginx frontend + optional backend) and
Apache host proxy configuration for deployment.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -33,3 +33,8 @@ pnpm-debug.log*
 .env
 .env.*
 !.env.example
+!deploy/.env.prod.example
+
+# Production build output (Apache DocumentRoot)
+deploy/dist/
+deploy/.env.prod