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/inmem_socket.go

@@ -0,0 +1,81 @@
+package sockets
+
+import (
+	"errors"
+	"net"
+	"sync"
+)
+
+var errClosed = errors.New("use of closed network connection")
+
+// InmemSocket implements net.Listener using in-memory only connections.
+type InmemSocket struct {
+	chConn  chan net.Conn
+	chClose chan struct{}
+	addr    string
+	mu      sync.Mutex
+}
+
+// dummyAddr is used to satisfy net.Addr for the in-mem socket
+// it is just stored as a string and returns the string for all calls
+type dummyAddr string
+
+// NewInmemSocket creates an in-memory only net.Listener
+// The addr argument can be any string, but is used to satisfy the `Addr()` part
+// of the net.Listener interface
+func NewInmemSocket(addr string, bufSize int) *InmemSocket {
+	return &InmemSocket{
+		chConn:  make(chan net.Conn, bufSize),
+		chClose: make(chan struct{}),
+		addr:    addr,
+	}
+}
+
+// Addr returns the socket's addr string to satisfy net.Listener
+func (s *InmemSocket) Addr() net.Addr {
+	return dummyAddr(s.addr)
+}
+
+// Accept implements the Accept method in the Listener interface; it waits for the next call and returns a generic Conn.
+func (s *InmemSocket) Accept() (net.Conn, error) {
+	select {
+	case conn := <-s.chConn:
+		return conn, nil
+	case <-s.chClose:
+		return nil, errClosed
+	}
+}
+
+// Close closes the listener. It will be unavailable for use once closed.
+func (s *InmemSocket) Close() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	select {
+	case <-s.chClose:
+	default:
+		close(s.chClose)
+	}
+	return nil
+}
+
+// Dial is used to establish a connection with the in-mem server
+func (s *InmemSocket) Dial(network, addr string) (net.Conn, error) {
+	srvConn, clientConn := net.Pipe()
+	select {
+	case s.chConn <- srvConn:
+	case <-s.chClose:
+		return nil, errClosed
+	}
+
+	return clientConn, nil
+}
+
+// Network returns the addr string, satisfies net.Addr
+func (a dummyAddr) Network() string {
+	return string(a)
+}
+
+// String returns the string form
+func (a dummyAddr) String() string {
+	return string(a)
+}