feat(analysis): worker daemon + real dispatcher + app wiring

The background analysis worker that drains analyze_page jobs:

- analysis::daemon: a lean sibling of the crawler daemon — leases only
  KIND_ANALYZE_PAGE, skip-if-done-unless-force, lease heartbeat, panic +
  timeout isolation, ack done/failed, and a failed page_analysis row on
  terminal (dead-lettered) failure. AnalyzeDispatcher trait seam.
- RealAnalyzeDispatcher: load page → storage.get → VisionClient.analyze →
  persist_analysis (skips a deleted page; caps image bytes).
- app::build spawns the daemon (own plain reqwest client) when
  ANALYSIS_ENABLED; AppHandle/main shut it down alongside the crawler.
- repo::page::find_by_id.

Tests: dispatch+ack-done, skip-when-done, force re-dispatch, terminal
failure writes failed row, panic isolation, ignores non-analyze jobs.

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

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.67.0",
+  "version": "0.68.0",
   "private": true,
   "type": "module",
   "scripts": {