Add Docker deployment configuration

- Add Dockerfile for production (multi-stage build)
- Add Dockerfile.dev for development with hot reload
- Add docker-compose.yml with 5 services (web, mariadb, redis, celery-worker, celery-beat)
- Add docker-compose.dev.yml for development overrides
- Add .dockerignore for optimized builds
- Add docker/entrypoint.sh startup script
- Add .env.docker.example template
- Add Makefile for common commands
- Add deploy.sh for one-command deployment
- Update config/settings/selfhosted.py to support MariaDB via DATABASE_URL
- Add mysqlclient to requirements.txt for MariaDB support
- Update .gitignore to exclude .env.docker

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitignore

@@ -17,6 +17,7 @@ media/
 
 # Environment
 .env
+.env.docker
 *.env.local
 
 # IDE