feat: Production readiness improvements for WHOOSH council formation

Major security, observability, and configuration improvements:

## Security Hardening
- Implemented configurable CORS (no more wildcards)
- Added comprehensive auth middleware for admin endpoints
- Enhanced webhook HMAC validation
- Added input validation and rate limiting
- Security headers and CSP policies

## Configuration Management
- Made N8N webhook URL configurable (WHOOSH_N8N_BASE_URL)
- Replaced all hardcoded endpoints with environment variables
- Added feature flags for LLM vs heuristic composition
- Gitea fetch hardening with EAGER_FILTER and FULL_RESCAN options

## API Completeness
- Implemented GetCouncilComposition function
- Added GET /api/v1/councils/{id} endpoint
- Council artifacts API (POST/GET /api/v1/councils/{id}/artifacts)
- /admin/health/details endpoint with component status
- Database lookup for repository URLs (no hardcoded fallbacks)

## Observability & Performance
- Added OpenTelemetry distributed tracing with goal/pulse correlation
- Performance optimization database indexes
- Comprehensive health monitoring
- Enhanced logging and error handling

## Infrastructure
- Production-ready P2P discovery (replaces mock implementation)
- Removed unused Redis configuration
- Enhanced Docker Swarm integration
- Added migration files for performance indexes

## Code Quality
- Comprehensive input validation
- Graceful error handling and failsafe fallbacks
- Backwards compatibility maintained
- Following security best practices

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

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

vendor/github.com/go-chi/chi/v5/CONTRIBUTING.md

@@ -0,0 +1,31 @@
+# Contributing
+
+## Prerequisites
+
+1. [Install Go][go-install].
+2. Download the sources and switch the working directory:
+
+    ```bash
+    go get -u -d github.com/go-chi/chi
+    cd $GOPATH/src/github.com/go-chi/chi
+    ```
+
+## Submitting a Pull Request
+
+A typical workflow is:
+
+1. [Fork the repository.][fork] [This tip maybe also helpful.][go-fork-tip]
+2. [Create a topic branch.][branch]
+3. Add tests for your change.
+4. Run `go test`. If your tests pass, return to the step 3.
+5. Implement the change and ensure the steps from the previous step pass.
+6. Run `goimports -w .`, to ensure the new code conforms to Go formatting guideline.
+7. [Add, commit and push your changes.][git-help]
+8. [Submit a pull request.][pull-req]
+
+[go-install]: https://golang.org/doc/install
+[go-fork-tip]: http://blog.campoy.cat/2014/03/github-and-go-forking-pull-requests-and.html
+[fork]: https://help.github.com/articles/fork-a-repo
+[branch]: http://learn.github.com/p/branching.html
+[git-help]: https://guides.github.com
+[pull-req]: https://help.github.com/articles/using-pull-requests