feat: load service adapters from ConfigMap, remove k8s API dependency

Adapters defined in config.yaml alongside routes and models.
Parsed by existing config loader, populated into registry at startup.
Removed: client-go deps, REST loader, informer, nginx proxy,
CiliumNetworkPolicy, apis/gateway/v1/ (duplicate types).
Kept: merged CI pipeline, imagePullPolicy Always, CA certs in Dockerfile.

cmd/gateway/main.go

@@ -53,7 +53,11 @@ func main() {
 	srv.SetHealthChecker(healthChecker)
 	
 	// Create ServiceAdapter registry and dispatcher (phase 8)
-	registry := serviceadapter.NewRegistry(nil) // nil uses default logger
+	registry := serviceadapter.NewRegistry(nil)
+	for _, a := range cfg.Adapters {
+		_ = registry.Add(a)
+	}
+	log.Printf("%d service adapters loaded", registry.Count())
 	dispatcher := serviceadapter.NewDispatcher(registry)
 
 	// Create router that handles health endpoints, X-Service (ServiceAdapter) routing,