fix(acceptance): 隔离容量压测并稳定数据库连接

将协议模拟验收的供应商并发限额与 Worker 容量门禁分离，真实金丝雀继续保留生产限流。readyz 改用关键连接池并预热关键及 River 池，延长生产连接空闲周期，降低跨地域连接抖动。失败 Run 现在可以原子替换且失败报告记录任务数量，避免 validation 之间短暂放开正式流量。\n\n验证：Go 全量测试、go vet、PostgreSQL 集成测试、ShellCheck、迁移安全、发布脚本、pnpm lint/test/build、OpenAPI 无漂移均通过。

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

@@ -28,7 +28,7 @@ source "$config_file"
 : "${AI_GATEWAY_DATABASE_RIVER_MAX_CONNS:=8}"
 : "${AI_GATEWAY_API_DATABASE_RIVER_MAX_CONNS:=4}"
 : "${AI_GATEWAY_DATABASE_MIN_IDLE_CONNS:=4}"
-: "${AI_GATEWAY_DATABASE_MAX_CONN_IDLE_SECONDS:=30}"
+: "${AI_GATEWAY_DATABASE_MAX_CONN_IDLE_SECONDS:=300}"
 : "${AI_GATEWAY_MEDIA_MATERIALIZATION_CONCURRENCY:=24}"
 : "${AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY:=24}"
 : "${AI_GATEWAY_WORKER_AUTOSCALING_ENABLED:=false}"

deploy/kubernetes/easyai-ai-gateway-cluster-release.conf.example

@@ -19,7 +19,7 @@ AI_GATEWAY_DATABASE_CRITICAL_MAX_CONNS=4
 AI_GATEWAY_DATABASE_RIVER_MAX_CONNS=8
 AI_GATEWAY_API_DATABASE_RIVER_MAX_CONNS=4
 AI_GATEWAY_DATABASE_MIN_IDLE_CONNS=4
-AI_GATEWAY_DATABASE_MAX_CONN_IDLE_SECONDS=30
+AI_GATEWAY_DATABASE_MAX_CONN_IDLE_SECONDS=300
 AI_GATEWAY_MEDIA_MATERIALIZATION_CONCURRENCY=24
 AI_GATEWAY_MEDIA_REQUEST_CONCURRENCY=24
 AI_GATEWAY_WORKER_AUTOSCALING_ENABLED=false