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.

internal/config/config.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"time"
+
+	"forgejo.riotpiao.com/rock/homelab-frontend/internal/serviceadapter"
 )
 
 // Config holds the gateway configuration.
@@ -18,6 +20,8 @@ type Config struct {
 	// Models maps model names to their upstream configuration.
 	// Multiple models can point to the same upstream address.
 	Models map[string]*ModelUpstream
+	// Adapters holds service adapter definitions for X-Service routing.
+	Adapters []*serviceadapter.ServiceAdapter
 }
 
 // ModelUpstream holds upstream configuration for a specific model.
@@ -94,16 +98,18 @@ func Load() (*Config, error) {
 		shutdownTimeout = d
 	}
 
-	// Load routes and models from config file
+	// Load routes, models, and adapters from config file
 	routes := make(map[string]*Route)
 	models := make(map[string]*ModelUpstream)
+	var adapters []*serviceadapter.ServiceAdapter
 	if configPath, ok := os.LookupEnv("CONFIG_PATH"); ok {
-		loadedRoutes, loadedModels, err := LoadRoutesAndModelsFromFile(configPath)
+		loadedRoutes, loadedModels, loadedAdapters, err := LoadRoutesAndModelsFromFile(configPath)
 		if err != nil {
 			return nil, err
 		}
 		routes = loadedRoutes
 		models = loadedModels
+		adapters = loadedAdapters
 	}
 
 	return &Config{
@@ -111,5 +117,6 @@ func Load() (*Config, error) {
 		ShutdownTimeout: shutdownTimeout,
 		Routes:          routes,
 		Models:          models,
+		Adapters:        adapters,
 	}, nil
 }