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/path_value_fallback.go

@@ -0,0 +1,19 @@
+//go:build !go1.22
+// +build !go1.22
+
+package chi
+
+import "net/http"
+
+// supportsPathValue is true if the Go version is 1.22 and above.
+//
+// If this is true, `net/http.Request` has methods `SetPathValue` and `PathValue`.
+const supportsPathValue = false
+
+// setPathValue sets the path values in the Request value
+// based on the provided request context.
+//
+// setPathValue is only supported in Go 1.22 and above so
+// this is just a blank function so that it compiles.
+func setPathValue(rctx *Context, r *http.Request) {
+}