feat(proxy): 实现代理节点批量升级回滚、隧道重定向跟随及远程配置管理

核心功能：
- 新增代理节点批量升级回滚工作流，支持分批升级、健康探针、跳过/重试/取消等操作
- proxy 隧道流处理器支持 HTTP 重定向跟随（最多 10 跳），区分 307/308 可重播与不可重播请求体
- proxy 协议新增 follow_redirects / http1_only 字段，网关侧同步支持
- 新增代理节点远端配置变更接口（名称、允许端口、调度状态、升级目标等）
- 新增代理节点注册/反注册/心跳的 Admin API，及节点过期清理维护任务
- gateway 隧道 owner-relay 支持流式代理大请求体，新增 5 MiB 默认限制
- 新增 ProxyNodeRegistrationMutation / ProxyNodeRemoteConfigMutation 数据类型
- proxy 配置新增重定向重播预算、心跳间隔等参数，TUI 安装向导同步更新
- 前端 ProxyNodes 页面新增批量升级操作面板及滚动进度展示

apps/aether-gateway/src/maintenance/runtime.rs

@@ -29,6 +29,10 @@ mod db_maintenance;
 mod pending_cleanup;
 #[path = "runtime/provider_checkin.rs"]
 mod provider_checkin;
+#[path = "runtime/proxy_node_staleness.rs"]
+mod proxy_node_staleness;
+#[path = "runtime/proxy_upgrade_rollout.rs"]
+mod proxy_upgrade_rollout;
 #[path = "runtime/request_candidate_cleanup.rs"]
 mod request_candidate_cleanup;
 #[path = "runtime/runners.rs"]
@@ -53,6 +57,18 @@ use config::*;
 use db_maintenance::*;
 use pending_cleanup::*;
 pub(crate) use provider_checkin::{perform_provider_checkin_once, ProviderCheckinRunSummary};
+use proxy_node_staleness::*;
+use proxy_upgrade_rollout::*;
+pub(crate) use proxy_upgrade_rollout::{
+    cancel_proxy_upgrade_rollout, clear_proxy_upgrade_rollout_conflicts,
+    collect_proxy_upgrade_rollout_probes, inspect_proxy_upgrade_rollout,
+    record_proxy_upgrade_traffic_success, restore_proxy_upgrade_rollout_skipped_nodes,
+    retry_proxy_upgrade_rollout_node, skip_proxy_upgrade_rollout_node, start_proxy_upgrade_rollout,
+    ProxyUpgradeRolloutCancelSummary, ProxyUpgradeRolloutConflictClearSummary,
+    ProxyUpgradeRolloutNodeActionSummary, ProxyUpgradeRolloutPendingProbe,
+    ProxyUpgradeRolloutProbeConfig, ProxyUpgradeRolloutSkippedRestoreSummary,
+    ProxyUpgradeRolloutStatus, ProxyUpgradeRolloutSummary, ProxyUpgradeRolloutTrackedNodeState,
+};
 use request_candidate_cleanup::*;
 use runners::*;
 use schedule::*;
@@ -71,6 +87,10 @@ pub(super) fn postgres_error(
 const AUDIT_LOG_CLEANUP_INTERVAL: Duration = Duration::from_secs(24 * 60 * 60);
 const GEMINI_FILE_MAPPING_CLEANUP_INTERVAL: Duration = Duration::from_secs(60 * 60);
 const PENDING_CLEANUP_INTERVAL: Duration = Duration::from_secs(5 * 60);
+const PROXY_NODE_STALE_SWEEP_INTERVAL: Duration = Duration::from_secs(30);
+const PROXY_UPGRADE_ROLLOUT_INTERVAL: Duration = Duration::from_secs(15);
+const PROXY_NODE_STALE_MIN_GRACE_SECS: u64 = 90;
+const PROXY_NODE_STALE_MISSED_HEARTBEATS: u64 = 3;
 const POOL_MONITOR_INTERVAL: Duration = Duration::from_secs(5 * 60);
 const PROVIDER_CHECKIN_CONCURRENCY: usize = 3;
 const PROVIDER_CHECKIN_DEFAULT_TIME: &str = "01:05";