feat(监控): 管理员排行榜实时并发监控 + 真正停止对话 + 409 中文化

- 排行榜页顶部新增「实时并发监控」面板（admin-only）：当前并发大模型调用数 +
  调用列表（用户/智能体/类型/已运行时长），每行「停止」+「全部停止」经
  RunManager.cancel 真正中断 LLM 流式调用，减轻大模型压力
- 并发量折线图（峰值/均值，按分钟/小时）：新增轻量后台采样器写入新表
  concurrency_samples（create_all 自动建表），可按分/时聚合
- 大模型出字速度折线图（tokens/秒，按分钟/小时）：复用 llm_call_metrics 聚合，
  便于定位是模型/供应商慢
- 后台采样可开关、默认关闭(opt-in)、运行时切换免重启、对线上零影响
  （单条极小 INSERT、保留期清理、查询有上限、全程 best-effort）
- 409 中文化：上一轮未结束又发新问题时返回中文提示，前端 onError 友好映射

后端：runtime/runs/manager.py(list_active)、persistence/concurrency(新模块)、
config/system_settings(ConcurrencyMonitorSettings)、gateway/routers/admin_active_runs、
app.py(采样后台任务)、services.py(409)。前端：core/admin/{active-runs,hooks}、
components/workspace/admin/concurrency-monitor、AdminUserLeaderboardPage、threads/hooks。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

offline-backend-20260512/backend/CLAUDE.md

@@ -297,6 +297,15 @@ Two on-demand/automatic refresh paths layer on top:
 - **Manual "????"** ? `POST /leaderboard/refresh-today` force-rebuilds *today's* snapshot **synchronously** (bounded by the same semaphore/timeout the scheduler uses), then returns the merged range. Lets an admin pull the latest real-time records into the stats without waiting for the TTL. Frontend: a "????" button on `AdminUserLeaderboardPage` ? `useRefreshTodayLeaderboard` (`core/admin/hooks.ts`), which primes + invalidates the `["admin-activity","leaderboard"]` query.
 - **Daily finalize of the previous day** ? once per day, on/after `ADMIN_LEADERBOARD_FINALIZE_HOUR` (local Beijing, default `1` = ?? 1 ?), the scheduler tick force-recomputes *yesterday* a single time so runs/tool-calls that only landed near midnight are fully captured. The decision is the pure `deerflow.persistence.admin_stats.finalize.should_finalize_previous_day` (status/generated_at/now/hour) ? the rebuild stamps `generated_at` to today, which self-debounces it for the rest of the day (no extra state file). Tests: `tests/test_leaderboard_finalize.py`.
 
+### Admin Concurrency Monitor (实时并发监控 / 系统压力)
+
+A live admin monitor embedded **at the top of `AdminUserLeaderboardPage`** (`components/workspace/admin/concurrency-monitor.tsx`, `ConcurrencyMonitorPanel`) that answers "当前有几个并发的大模型调用、是谁、能不能直接停掉" and charts system pressure over time. Built on the existing in-memory `RunManager` (no new run plumbing).
+
+- **Live concurrency + 真正停止** — `RunManager.list_active()` returns every run whose status is `pending`/`running` (the registry keeps finished records around until `cleanup`, so it filters by status). `len(list_active())` is the current concurrent-call count. Router `app/gateway/routers/admin_active_runs.py` (`/api/admin/active-runs`, **admin only** via the shared `admin_users._require_admin`): `GET /` returns `{count, server_time, runs:[{run_id, thread_id, status, created_at, elapsed_seconds, user_id, user_name, agent_id, agent_name, thread_title, kind, multitask_strategy}]}` — each run best-effort enriched (batched DB) with the owning user's email (`threads_meta.user_id`→`users.email`) and the agent's display name (`agents.name`); `kind` is derived from thread metadata (圆桌会商 / 系统/后台 / 任务对话 / 对话). `POST /{run_id}/cancel` calls `RunManager.cancel(run_id, action="interrupt")`, which sets the abort event **and cancels the run's asyncio task** — i.e. it truly aborts the in-flight model stream, freeing capacity. `POST /cancel-all` stops every in-flight run.
+- **并发量折线图 (按分钟/小时)** — a lightweight background **sampler** (`_concurrency_sampler_loop` in `app/gateway/app.py`, singleton file-locked, started in the lifespan) records `len(list_active())` every `CONCURRENCY_SAMPLE_INTERVAL_SECONDS` (default 15s) into the new `concurrency_samples` table (`deerflow.persistence.concurrency`, `ConcurrencySampleRow{sampled_at, active_count}`, auto-created by `create_all`, **no migration**; store wired as `app.state.concurrency_sample_store`). ~Hourly it purges rows older than `CONCURRENCY_SAMPLE_RETENTION_HOURS` (default 168h). `GET /concurrency?granularity=minute|hour&hours=N` aggregates samples into per-bucket **peak + avg** (`ConcurrencySampleStore.aggregate`, bucketed in Python so it's identical across sqlite/mysql/postgres; fetch capped at 60k rows). Default lookback: minute→3h, hour→48h.
+- **大模型出字速度折线图 (tokens/sec, 按分钟/小时)** — `GET /token-speed?granularity=&hours=` aggregates the persisted `llm_call_metrics` (`status="success"`) into per-bucket avg/min/max tokens/sec (deriving tokens/sec from `output_tokens÷duration_ms` when the stored value is null). A dip pinpoints the model/provider as the bottleneck for that window — "知道具体原因出现在哪里".
+- **On/off + 不影响线上** — the whole feature is designed to never impact production: sampling is one tiny INSERT, retention-purged, all paths best-effort/guarded, queries bounded. A **runtime switch** lives in `system_settings.json → concurrency_monitor.enabled` (`ConcurrencyMonitorSettings`, **default false / opt-in**, mtime-hot-reloaded): the background loop always runs (just sleeps) but only samples when an admin turns it on, and it re-reads the flag **every tick** so toggling it on/off **takes effect immediately without a restart** (the on-demand live snapshot + 停止 stay available regardless; only the historical chart needs sampling on). `GET|PUT /api/admin/active-runs/settings` reads/writes it (admin only); the panel's 「后台采样」 Switch drives it. Env `CONCURRENCY_SAMPLE_ENABLED=0` is a hard master kill (never starts the loop). Frontend client/hooks: `core/admin/active-runs.ts` + `core/admin/hooks.ts` (`useActiveRuns` polls 4s while the panel is open, `useConcurrencySeries`/`useTokenSpeedSeries` poll 15s, `useCancelActiveRun`/`useCancelAllActiveRuns`, `useMonitorSettings`/`useUpdateMonitorSettings`). Tests: `tests/test_concurrency_monitor.py`.
+
 ### Scheduled Task Runtime
 
 `ScheduledTaskService` (`deerflow/runtime/scheduler/service.py`) polls due tasks every `poll_interval_seconds` and executes each in its own throwaway thread, serialized by a shared `_agent_run_lock`.