perf(acceptance): 解耦 API 媒体请求并发

生产同构验收将 API 请求体并发独立配置为 AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY，默认每个 API 128；Worker 执行槽和媒体物化仍按 P24/P28/P32 阶梯变化。\n\n这避免同步 Gemini 请求在整个任务生命周期占用仅 24/28/32 个入口槽，并继续由 RSS 与节点内存门禁验证安全上限。\n\n验证：bash -n；shellcheck -x；git diff --check。

scripts/cluster/run-production-acceptance.sh

@@ -29,6 +29,7 @@ Optional model overrides (otherwise selected from current production candidates)
   AI_GATEWAY_ACCEPTANCE_VIDEO_MODEL
   AI_GATEWAY_ACCEPTANCE_GATEWAY_TLS_SERVER_NAME
   AI_GATEWAY_ACCEPTANCE_IDENTITY_SHARDS
+  AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY
 EOF
 }
 
@@ -53,6 +54,7 @@ require_commands curl git jq node openssl sed
 : "${AI_GATEWAY_ACCEPTANCE_GEMINI_MODEL:=}"
 : "${AI_GATEWAY_ACCEPTANCE_VIDEO_MODEL:=}"
 : "${AI_GATEWAY_ACCEPTANCE_API_DATABASE_MAX_CONNS:=64}"
+: "${AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY:=128}"
 : "${AI_GATEWAY_ACCEPTANCE_IDENTITY_SHARDS:=32}"
 : "${AI_GATEWAY_ACCEPTANCE_GATEWAY_TLS_SERVER_NAME:=}"
 : "${AI_GATEWAY_ACCEPTANCE_GATEWAYS:?}"
@@ -62,6 +64,11 @@ require_commands curl git jq node openssl sed
   echo 'AI_GATEWAY_ACCEPTANCE_API_DATABASE_MAX_CONNS must be between 1 and 256' >&2
   exit 1
 }
+[[ $AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY =~ ^[1-9][0-9]*$ &&
+   $AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY -le 1024 ]] || {
+  echo 'AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY must be between 1 and 1024' >&2
+  exit 1
+}
 [[ $AI_GATEWAY_ACCEPTANCE_IDENTITY_SHARDS =~ ^[1-9][0-9]*$ &&
    $AI_GATEWAY_ACCEPTANCE_IDENTITY_SHARDS -le 128 ]] || {
   echo 'AI_GATEWAY_ACCEPTANCE_IDENTITY_SHARDS must be between 1 and 128' >&2
@@ -897,7 +904,7 @@ apply_capacity_profile() {
       "AI_GATEWAY_DATABASE_MIN_IDLE_CONNS=$min_idle" \
       "AI_GATEWAY_DATABASE_MAX_CONN_IDLE_SECONDS=$max_idle_seconds" \
       "AI_GATEWAY_MEDIA_MATERIALIZATION_CONCURRENCY=$media" \
-      "AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY=$media" >/dev/null
+      "AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY=$AI_GATEWAY_ACCEPTANCE_API_MEDIA_REQUEST_CONCURRENCY" >/dev/null
     remote_kubectl rollout status "deployment/easyai-api-$site" \
       -n "$namespace" --timeout=300s
   done