feat(routing): 引入多执行池智能调度

将 Worker 发现、路由画像、容量与执行传输抽象为平台无关接口，新增 Kubernetes 和静态容量适配器，并以 shadow 模式接入生产配置。

实现网络与容量评分、路由防抖、池队列、同步 Worker 租约、一次性执行令牌，以及提交状态不明时禁止重复分配的安全语义。

新增 0105 兼容迁移、管理接口、指标、OpenAPI 和回归测试。已执行全量 Go 测试、go vet、OpenAPI、迁移安全、Compose 与 Kustomize 验证。

apps/api/internal/store/rate_limits.go

@@ -691,13 +691,13 @@ ON CONFLICT (task_id, event_type) DO NOTHING`, releaseBillingTaskIDs); err != ni
 	tag, err := tx.Exec(ctx, `
 UPDATE gateway_task_attempts attempt
 SET status = 'failed',
-    retryable = task.error_code IS DISTINCT FROM 'upstream_submission_unknown',
+    retryable = task.submission_state IS DISTINCT FROM 'submission_confirmation_pending',
     error_code = CASE
-      WHEN task.error_code = 'upstream_submission_unknown' THEN 'upstream_submission_unknown'
+      WHEN task.submission_state = 'submission_confirmation_pending' THEN 'upstream_timeout'
       ELSE 'execution_lease_expired'
     END,
     error_message = CASE
-      WHEN task.error_code = 'upstream_submission_unknown' THEN 'upstream submission result is unknown'
+      WHEN task.submission_state = 'submission_confirmation_pending' THEN 'upstream submission confirmation timed out'
       ELSE 'attempt execution lease expired after worker heartbeat became stale'
     END,
     finished_at = now()