Move network debugging docs to separate gitignored file

Extract infrastructure/proxy debugging information from CLAUDE.md
into unturf-debugging.md to avoid exposing internal network details.

- Created unturf-debugging.md with full proxy chain documentation
- Added unturf-debugging.md to .gitignore
- Simplified CLAUDE.md to reference debugging doc
- Documented Caddy configuration (not nginx)
- Included troubleshooting steps for 502 errors

This keeps sensitive infrastructure details out of the public repo
while maintaining documentation for internal debugging.

.gitignore

@@ -10,3 +10,4 @@ samconfig.toml
 vars.sh
 .coverage
 htmlcov/
+unturf-debugging.md

CLAUDE.md

@@ -35,6 +35,7 @@
 - Use `vars.sh` to set up environment variables
 - Required: MODEL_ENDPOINT_x and MODEL_API_KEY_x variables for AI models
 - Run with: `source vars.sh && python app.py`
+- **NEVER cat or grep vars.sh** - it contains API keys and secrets
 
 ### Makefile Commands
 - `make venv` - Create virtual environment and install dependencies
@@ -42,6 +43,12 @@
 - `make test` - Run all tests
 - `make dev-setup` - Install development dependencies
 
+### Network Infrastructure
+
+- OpenCompletion uses Caddy for web server (not nginx)
+- Multi-layer proxy architecture for accessing AI models
+- See `unturf-debugging.md` for network troubleshooting (gitignored)
+
 ## OpenCompletion Architecture
 
 ### Frontend Structure