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/docker/go-connections/sockets/proxy.go

@@ -0,0 +1,51 @@
+package sockets
+
+import (
+	"net"
+	"net/url"
+	"os"
+	"strings"
+
+	"golang.org/x/net/proxy"
+)
+
+// GetProxyEnv allows access to the uppercase and the lowercase forms of
+// proxy-related variables.  See the Go specification for details on these
+// variables. https://golang.org/pkg/net/http/
+func GetProxyEnv(key string) string {
+	proxyValue := os.Getenv(strings.ToUpper(key))
+	if proxyValue == "" {
+		return os.Getenv(strings.ToLower(key))
+	}
+	return proxyValue
+}
+
+// DialerFromEnvironment takes in a "direct" *net.Dialer and returns a
+// proxy.Dialer which will route the connections through the proxy using the
+// given dialer.
+func DialerFromEnvironment(direct *net.Dialer) (proxy.Dialer, error) {
+	allProxy := GetProxyEnv("all_proxy")
+	if len(allProxy) == 0 {
+		return direct, nil
+	}
+
+	proxyURL, err := url.Parse(allProxy)
+	if err != nil {
+		return direct, err
+	}
+
+	proxyFromURL, err := proxy.FromURL(proxyURL, direct)
+	if err != nil {
+		return direct, err
+	}
+
+	noProxy := GetProxyEnv("no_proxy")
+	if len(noProxy) == 0 {
+		return proxyFromURL, nil
+	}
+
+	perHost := proxy.NewPerHost(proxyFromURL, direct)
+	perHost.AddFromString(noProxy)
+
+	return perHost, nil
+}