fix(acceptance): 阻断本地控制面漂移污染验收

本地 K3s 节点此前在 Kubelet 中登记为宿主机资源，负载可挤压 etcd 并在 server 重启后继续污染同一 Run。现在为三节点设置真实可调度预算、独立 etcd/数据卷和锁定依赖镜像，并持续核对 server 与 API/etcd 健康。\n\n每次验收生成独立 Run ID，报告使用独占或原子写入，负载错误记录具体阶段；数据库鉴权不可用返回带 Retry-After 的 503，避免基础设施故障被误报为 401。\n\n验证：Go 全量测试、go vet、gofmt、OpenAPI、bash -n、ShellCheck、报告测试和 k3d 配置解析均通过。

apps/api/docs/swagger.yaml

@@ -7680,6 +7680,10 @@ paths:
           description: Gone
           schema:
             $ref: '#/definitions/httpapi.EasyAIGeneratedResponse'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
       security:
       - BearerAuth: []
       summary: 查询 server-main EasyAIClient 兼容任务结果
@@ -8248,6 +8252,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.VolcesErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.VolcesErrorEnvelope'
       security:
       - BearerAuth: []
       summary: 创建火山内容生成任务
@@ -8945,6 +8953,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.GeminiErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.GeminiErrorEnvelope'
       security:
       - BearerAuth: []
       summary: Gemini generateContent 兼容接口
@@ -8993,6 +9005,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.GeminiErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.GeminiErrorEnvelope'
       security:
       - BearerAuth: []
       summary: Gemini generateContent 兼容接口
@@ -9058,6 +9074,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.ErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
         "504":
           description: Gateway Timeout
           schema:
@@ -9623,6 +9643,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.ErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
         "504":
           description: Gateway Timeout
           schema:
@@ -9692,6 +9716,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.ErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
         "504":
           description: Gateway Timeout
           schema:
@@ -9980,6 +10008,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.ErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
         "504":
           description: Gateway Timeout
           schema:
@@ -10192,6 +10224,10 @@ paths:
           description: Bad Gateway
           schema:
             $ref: '#/definitions/httpapi.ErrorEnvelope'
+        "503":
+          description: Service Unavailable
+          schema:
+            $ref: '#/definitions/httpapi.ErrorEnvelope'
         "504":
           description: Gateway Timeout
           schema: