fix(api): Use in-cluster K8s config for executor in K8s pods

- Try load_incluster_config() first (for pods running in K8s)
- Fallback to kubeconfig file (for local development)
- Fixes "K8s connection not available" error in production

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/services/executor.py

@@ -98,6 +98,10 @@ class ActionExecutor:
         """
         初始化 K8s 連線
 
+        優先順序:
+        1. In-cluster 配置 (ServiceAccount Token) - 用於 K8s Pod 內部
+        2. Kubeconfig 檔案 - 用於本地開發
+
         Returns:
             bool: 是否成功初始化
         """
@@ -106,23 +110,34 @@ class ActionExecutor:
 
         try:
             from kubernetes_asyncio import client
-            from kubernetes_asyncio.config import load_kube_config
+            from kubernetes_asyncio.config import (
+                load_incluster_config,
+                load_kube_config,
+                ConfigException,
+            )
 
-            # 檢查 kubeconfig 檔案
-            kubeconfig_path = Path(settings.KUBECONFIG_PATH)
-            if not kubeconfig_path.is_absolute():
-                # 相對路徑基於 apps/api/
-                kubeconfig_path = Path(__file__).parent.parent.parent / settings.KUBECONFIG_PATH
+            config_source = None
 
-            if not kubeconfig_path.exists():
-                logger.error(
-                    "kubeconfig_not_found",
-                    path=str(kubeconfig_path),
-                )
-                return False
+            # 優先嘗試 in-cluster 配置 (K8s Pod 內部)
+            try:
+                load_incluster_config()
+                config_source = "in-cluster"
+                logger.info("k8s_using_incluster_config")
+            except ConfigException:
+                # 不在 K8s 內部，嘗試 kubeconfig 檔案
+                kubeconfig_path = Path(settings.KUBECONFIG_PATH)
+                if not kubeconfig_path.is_absolute():
+                    kubeconfig_path = Path(__file__).parent.parent.parent / settings.KUBECONFIG_PATH
 
-            # 載入 kubeconfig
-            await load_kube_config(config_file=str(kubeconfig_path))
+                if not kubeconfig_path.exists():
+                    logger.error(
+                        "kubeconfig_not_found",
+                        path=str(kubeconfig_path),
+                    )
+                    return False
+
+                await load_kube_config(config_file=str(kubeconfig_path))
+                config_source = str(kubeconfig_path)
 
             # 建立 API clients
             self._api_client = client.ApiClient()
@@ -132,7 +147,7 @@ class ActionExecutor:
             self._initialized = True
             logger.info(
                 "k8s_executor_initialized",
-                kubeconfig=str(kubeconfig_path),
+                config_source=config_source,
             )
             return True