fix(publish): prevent stuck publish queue and duplicate posting

The desktop publish queue could stall for a long time and end users assumed
the software was broken. Root cause: a hung adapter held its execution slot
with no wall-clock timeout while auto-renewing its lease forever, so the
server never reclaimed it and every queued task behind it stayed 等待发布.
Auto-recovery also risked silently re-posting a non-idempotent article.

Client (Electron):
- per-task wall-clock deadline + abort; progress-gated lease renewal that
  stops and aborts a stalled task instead of renewing it forever
- decouple the concurrency cap from CDP-induced CPU/memory pressure
  (admission gate instead of self-throttling collapse); 15s watchdog pump
- all adapter network I/O now has fetch timeouts and honors context.signal;
  bounded image-upload concurrency with per-image timeout
- surface live adapter progress, elapsed time, queue position and a
  working-vs-queued distinction in the publish view

Server (tenant-api):
- publish lease-recovery worker (every 3m) + supporting index: reclaim
  expired in_progress publish leases, requeue (<3 attempts) or terminal-fail
- 3-minute lease TTL with client-presence-gated extension; max 3 attempts

Idempotency (production-grade core):
- durable publish_submit_started_at marker, set before the irreversible
  platform submit POST; recovery and abort route a maybe-submitted task to
  unknown (manual reconcile, kept in the dedup set) instead of re-posting
- desktop UI requires explicit confirmation before retrying a possibly-
  already-published task

Verified: go build/vet/test (incl. resolvePublishRecoveryOutcome), vue-tsc,
vitest 141/141, gofmt all clean.

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

apps/desktop-client/src/main/adapters/media-image.ts

@@ -3,6 +3,7 @@ import { Buffer } from 'node:buffer'
 import { nativeImage } from 'electron'
 
 import { fetchDesktopApiURL, resolveDesktopApiURL } from '../transport/api-client'
+import { adapterFetch, mergeAbortSignals, timeoutSignal, type AdapterFetchOptions } from './common'
 
 export interface ImageAssetBlob {
   blob: Blob
@@ -97,10 +98,20 @@ function fileNameForImageType(sourceType: string): string {
   return 'image.png'
 }
 
-export async function fetchImageAssetBlob(sourceUrl: string): Promise<ImageAssetBlob | null> {
+export async function fetchImageAssetBlob(
+  sourceUrl: string,
+  options: AdapterFetchOptions = {},
+): Promise<ImageAssetBlob | null> {
   for (const candidate of buildAssetURLCandidates(sourceUrl)) {
     const response = await (
-      shouldUseDesktopAssetFetch(candidate) ? fetchDesktopApiURL(candidate) : fetch(candidate)
+      shouldUseDesktopAssetFetch(candidate)
+        ? fetchDesktopApiURL(candidate, {
+            signal: mergeAbortSignals([
+              options.signal,
+              timeoutSignal(options.timeoutMs ?? 10_000),
+            ]),
+          })
+        : adapterFetch(candidate, {}, { timeoutMs: options.timeoutMs ?? 10_000, signal: options.signal })
     ).catch(() => null)
     if (!response?.ok) {
       continue