feat(desktop): add monitor scheduler, Playwright CDP layer, and account health

Move monitor-task scheduling authority onto the client with a durable
file-backed queue that survives restart, drops stale cross-day tasks,
enforces per-platform serialism, and adapts global concurrency from
Electron process metrics. Publish tasks keep their existing FIFO.

Add a hidden Playwright CDP manager that attaches to Electron Chromium
on account session partitions, lets adapters opt into `executionMode:
"playwright"`, and leaves the existing hidden WebContentsView path in
place for current adapters.

Introduce an account-health subsystem with silent probes, projected
health/auth states, and IPC invalidation events so the renderer can
show accurate auth/probe status and verification timestamps.

Server-side, derive and forward title/business_date/scheduler_group_key/
question_text metadata on desktop task events so the local scheduler
can defer same-question fan-out before leasing.

apps/desktop-client/src/renderer/env.d.ts

@@ -29,6 +29,9 @@ declare global {
         retryPublishTask(taskId: string): Promise<CreatePublishJobResponse>;
         syncRuntimeSession(session: DesktopRuntimeSessionSyncRequest | null): Promise<null>;
         releaseRuntimeSession(revoke?: boolean): Promise<null>;
+        onRuntimeInvalidated(
+          listener: (event: { reason: "account-health"; at: number }) => void,
+        ): () => void;
       };
     };
   }