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/jackc/pgx/v5/pgconn/krb5.go

@@ -0,0 +1,100 @@
+package pgconn
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgproto3"
+)
+
+// NewGSSFunc creates a GSS authentication provider, for use with
+// RegisterGSSProvider.
+type NewGSSFunc func() (GSS, error)
+
+var newGSS NewGSSFunc
+
+// RegisterGSSProvider registers a GSS authentication provider. For example, if
+// you need to use Kerberos to authenticate with your server, add this to your
+// main package:
+//
+//	import "github.com/otan/gopgkrb5"
+//
+//	func init() {
+//		pgconn.RegisterGSSProvider(func() (pgconn.GSS, error) { return gopgkrb5.NewGSS() })
+//	}
+func RegisterGSSProvider(newGSSArg NewGSSFunc) {
+	newGSS = newGSSArg
+}
+
+// GSS provides GSSAPI authentication (e.g., Kerberos).
+type GSS interface {
+	GetInitToken(host string, service string) ([]byte, error)
+	GetInitTokenFromSPN(spn string) ([]byte, error)
+	Continue(inToken []byte) (done bool, outToken []byte, err error)
+}
+
+func (c *PgConn) gssAuth() error {
+	if newGSS == nil {
+		return errors.New("kerberos error: no GSSAPI provider registered, see https://github.com/otan/gopgkrb5")
+	}
+	cli, err := newGSS()
+	if err != nil {
+		return err
+	}
+
+	var nextData []byte
+	if c.config.KerberosSpn != "" {
+		// Use the supplied SPN if provided.
+		nextData, err = cli.GetInitTokenFromSPN(c.config.KerberosSpn)
+	} else {
+		// Allow the kerberos service name to be overridden
+		service := "postgres"
+		if c.config.KerberosSrvName != "" {
+			service = c.config.KerberosSrvName
+		}
+		nextData, err = cli.GetInitToken(c.config.Host, service)
+	}
+	if err != nil {
+		return err
+	}
+
+	for {
+		gssResponse := &pgproto3.GSSResponse{
+			Data: nextData,
+		}
+		c.frontend.Send(gssResponse)
+		err = c.flushWithPotentialWriteReadDeadlock()
+		if err != nil {
+			return err
+		}
+		resp, err := c.rxGSSContinue()
+		if err != nil {
+			return err
+		}
+		var done bool
+		done, nextData, err = cli.Continue(resp.Data)
+		if err != nil {
+			return err
+		}
+		if done {
+			break
+		}
+	}
+	return nil
+}
+
+func (c *PgConn) rxGSSContinue() (*pgproto3.AuthenticationGSSContinue, error) {
+	msg, err := c.receiveMessage()
+	if err != nil {
+		return nil, err
+	}
+
+	switch m := msg.(type) {
+	case *pgproto3.AuthenticationGSSContinue:
+		return m, nil
+	case *pgproto3.ErrorResponse:
+		return nil, ErrorResponseToPgError(m)
+	}
+
+	return nil, fmt.Errorf("expected AuthenticationGSSContinue message but received unexpected message %T", msg)
+}