feat: add Dockerfile, compose.yml, gunicorn config, http utilities, and static assets

Add Dockerfile with wkhtmltopdf multi-stage build and gunicorn entrypoint for production deployment. Introduce compose.yml with volume sync for development. Switch Makefile from snek.serve to gunicorn with aiohttp worker. Extend Application class with CORS middleware, static file serving, login/test/http-get/http-photo routes, and template rendering. Create gunicorn.py entrypoint, http.py module with async URL fetching, screenshot generation via imgkit, link repair, and CRC32-based caching. Add middleware.py with CORS handlers. Include static assets: app.js with Message/Room/App classes, html_frame.css/js custom element, and prachtig-gitter_like.html UI template. Update setup.cfg dependencies with beautifulsoup4, gunicorn, imgkit, wkhtmltopdf. Add *.png to .gitignore.

.gitignore

@@ -1,7 +1,7 @@
 .vscode
 .history
 *.db*
-
+*.png
 # ---> Python
 # Byte-compiled / optimized / DLL files
 __pycache__/