fix(acceptance): 纳入 API 数据库池容量门禁

高并发 Gemini 验收暴露两地 API 数据库池仍固定为 16，导致连接池满载、readiness 失败且压力曲线只监测 Worker，无法及时识别真实瓶颈。\n\n将容量档位的数据库连接池同步应用到 API，发布工具和生产清单保持同一配置；压力采样及日志门禁覆盖 API 与 Worker 四个连接池，并在失败时保留验收 JSON 报告。\n\n验证：bash -n、ShellCheck、kubectl kustomize、git diff --check。

deploy/kubernetes/easyai-ai-gateway-cluster-release

@@ -145,7 +145,8 @@ rollout_worker_site() {
 rollout_api_capacity_site() {
   local site=$1
   "${kubectl[@]}" set env "deployment/easyai-api-$site" -n "$NAMESPACE" \
-    "AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT=$AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT"
+    "AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT=$AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT" \
+    "AI_GATEWAY_DATABASE_MAX_CONNS=$AI_GATEWAY_DATABASE_MAX_CONNS"
   "${kubectl[@]}" rollout status "deployment/easyai-api-$site" -n "$NAMESPACE" --timeout=300s
 }
 
@@ -168,7 +169,8 @@ rollout_site() {
   local web_changed=$5
   if [[ $api_changed == true ]]; then
     "${kubectl[@]}" set env "deployment/easyai-api-$site" -n "$NAMESPACE" \
-      "AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT=$AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT"
+      "AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT=$AI_GATEWAY_ASYNC_WORKER_HARD_LIMIT" \
+      "AI_GATEWAY_DATABASE_MAX_CONNS=$AI_GATEWAY_DATABASE_MAX_CONNS"
     "${kubectl[@]}" set image "deployment/easyai-api-$site" -n "$NAMESPACE" \
       "api=$api_image"
     "${kubectl[@]}" rollout status "deployment/easyai-api-$site" -n "$NAMESPACE" --timeout=300s

deploy/kubernetes/production/application.yaml

@@ -53,7 +53,7 @@ spec:
             - name: AI_GATEWAY_ASYNC_QUEUE_WORKER_ENABLED
               value: "false"
             - name: AI_GATEWAY_DATABASE_MAX_CONNS
-              value: "16"
+              value: "32"
             - name: AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY
               value: "16"
             - name: AI_GATEWAY_MEDIA_MATERIALIZATION_CONCURRENCY
@@ -182,7 +182,7 @@ spec:
             - name: AI_GATEWAY_ASYNC_QUEUE_WORKER_ENABLED
               value: "false"
             - name: AI_GATEWAY_DATABASE_MAX_CONNS
-              value: "16"
+              value: "32"
             - name: AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY
               value: "16"
             - name: AI_GATEWAY_MEDIA_MATERIALIZATION_CONCURRENCY