feat: 编排器跨项目全局并发上限闸（tsk_erQHNYdn6i9g）

新增用户级设置项 globalConcurrency（settings 表，独立于新建项目默认值
来源 concurrency），缺省 0 = 不限，向后兼容无需 DB 迁移。

- store: UserSettings 加 globalConcurrency 字段 + 默认 0；新增
  globalInflightCount()（跨所有项目 started run 总数，与 inflightTaskIds 同口径）
- orchestrator.claimTick: 叠加全局闸，与 per-project 闸串联（都过才领）；
  轮初查一次全局在途、轮内手动 ++，达上限即 return 跨所有项目停止领取
- api: PUT /api/settings 支持 globalConcurrency（空/null 归一为 0）
- web: 侧栏「全局设置」入口 + 模态，编辑/回显/校验（≥0 整数）
- test: 新增全局闸达上限跨项目阻止 / 未达上限正常领取 / 边界 / 轮初短路 用例

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/api/server.ts

@@ -137,6 +137,8 @@ export function buildServer(opts: ApiOptions): FastifyInstance {
     if (b.budgetUsd !== undefined) patch.budgetUsd = b.budgetUsd === null || b.budgetUsd === '' ? null : Number(b.budgetUsd);
     if (b.budgetPeriod !== undefined) patch.budgetPeriod = b.budgetPeriod as 'day' | 'month';
     if (b.model !== undefined) patch.model = b.model === null || b.model === '' ? null : String(b.model);
+    if (b.globalConcurrency !== undefined)
+      patch.globalConcurrency = b.globalConcurrency === null || b.globalConcurrency === '' ? 0 : Number(b.globalConcurrency);
     return store.putSettings(patch);
   });
 

src/daemon/orchestrator.ts

@@ -209,9 +209,16 @@ export function createOrchestrator(store: Store, log: OrchestratorLogger, deps:
   /**
    * 领取轮：对每个 active 且 autonomy≠manual 的项目，并发闸 = inflightTaskIds（有 started run 的任务，
    * executor + planner 通用）。在 active<concurrency 时按 claimable 领新任务并 spawn worker。
+   *
+   * 全局并发闸（settings.globalConcurrency，0/缺省=不限）与 per-project 闸【串联】：两闸都过才领。
+   * 全局在途总数（globalActive）轮初查一次、轮内手动 ++（claimOne 同步起新 started run），命中即 return——
+   * 达上限后任何项目都不应再领，故 return（跨所有项目停止）而非 break（只停当前项目）。
    */
   function claimTick(): void {
     try {
+      const cap = store.getSettings().globalConcurrency;        // 0/缺省 = 不限
+      let globalActive = store.globalInflightCount();           // 轮初的全局在途总数
+      if (cap > 0 && globalActive >= cap) return;               // 全局闸已满 → 整轮跨项目都不领
       for (const p of store.listProjects()) {
         if (p.status !== 'active' || p.autonomy === 'manual') continue;
         const inflight = store.inflightTaskIds(p.id);
@@ -219,9 +226,11 @@ export function createOrchestrator(store: Store, log: OrchestratorLogger, deps:
         if (active >= p.concurrency) continue;
 
         for (const { task, score } of claimable(p, inflight)) {
-          if (active >= p.concurrency) break;
+          if (active >= p.concurrency) break;                   // per-project 闸
+          if (cap > 0 && globalActive >= cap) return;           // 全局闸：达上限即跨所有项目停止领取
           claimOne(p, task, score);
           active++;
+          globalActive++;                                       // 本轮内手动累加（claimOne 已起新 started run）
         }
       }
     } catch (e) {

src/store/store.ts

@@ -30,11 +30,14 @@ export interface UserSettings {
   budgetUsd: number | null;
   budgetPeriod: 'day' | 'month';
   model: string | null;
+  /** 跨所有项目的在途 run 总数上限（全局并发闸）；0 = 不限。与 concurrency（新建项目默认值）相互独立。 */
+  globalConcurrency: number;
 }
 const SETTINGS_DEFAULT: UserSettings = {
   autonomy: 'manual', concurrency: 1, maxRetries: 2, timeoutMs: 1_800_000,
   autoApprovePlan: false, autoApproveExec: false,
   budgetUsd: null, budgetPeriod: 'month', model: null,
+  globalConcurrency: 0,
 };
 const id = (prefix: string): string => `${prefix}_${nanoid(12)}`;
 
@@ -918,6 +921,11 @@ export class Store {
     return new Set(rows.map((r) => r.tid));
   }
 
+  /** 跨所有项目的在途 run 总数（全局并发闸用；与 inflightTaskIds 同口径=started run，覆盖 executor + planner）。 */
+  globalInflightCount(): number {
+    return (this.db.prepare(`SELECT COUNT(*) AS n FROM runs WHERE status = 'started'`).get() as { n: number }).n;
+  }
+
   /** 所有 started run + 其任务（reap / ingest / reconcile 通用，覆盖 executor + planner + 残留复审 run）。 */
   liveRunsWithTask(): Array<{ task: Task; run: Run }> {
     const runs = this.db.prepare(`SELECT * FROM runs WHERE status = 'started' ORDER BY started_at`).all() as RunRow[];