Prepare for public git: .gitignore, .env, sanitized configs

- Add .gitignore excluding .env, __pycache__, test_files (copyrighted PDFs),
  session logs, marker/ submodule, and other generated/private files
- Add .env with local config (gitignored); expand .env.example with all
  supported environment variables
- docker-compose.yml: all hardcoded values now use default pattern
- Containerfile: install marker-pdf from GitHub instead of local submodule;
  fix AMD_COMPUTE default to false; sanitize default OLLAMA_HOST
- Remove marker/ submodule from git tracking (keep local checkout via .gitignore)
- Remove session transcript and copyrighted ENISA PDFs from git tracking
- Sanitize local IPs in README, kubernetes deployment, deploy-podman.sh
- Fix hardcoded paths in convert_both.py and compare_conversions.py
- Update requirements.txt to reference GitHub instead of local --editable

requirements.txt

@@ -2,6 +2,9 @@
 flask>=3.0,<4.0
 gunicorn>=21.2,<23.0
 
-# marker dependencies — install from the cloned marker with full format extras
---editable ./marker[full]
+# marker-pdf — document conversion engine
+# For local development from a clone:
+#   pip install -e ./marker[full]
+# For production from GitHub:
+marker-pdf[full] @ git+https://github.com/VikParuchuri/marker.git