chore: consolidate all persistent data into ./data folder

- Update docker-compose.yml to mount Caddyfile from ./data
- Remove Dockerfile directory creation - handled by init-data.sh
- Add init-data.sh script to initialize ./data with all required files
- Add DATA_DEPLOYMENT.md documentation for deployment workflow
- Update .gitignore to exclude ./data folder
- All persistent data (app, config, database, uploads) now centralized in ./data

Dockerfile

@@ -31,9 +31,6 @@ COPY . .
 COPY docker-entrypoint.sh /docker-entrypoint.sh
 RUN chmod +x /docker-entrypoint.sh
 
-# Create directories for uploads and database
-RUN mkdir -p app/static/uploads instance
-
 # Set environment variables
 ENV FLASK_APP=app.app:create_app
 ENV PYTHONUNBUFFERED=1