Phase 6: sync jobs, inquiry and order forms

- Sync scheduler in the content service with a per-job cache (sync_cache),
  sync_runs reporting and Healthchecks pings. Jobs: Archidekt, BoardGameGeek,
  cover art (Open Library, TMDB, AniList), Suwayomi and Kavita reading
  progress, Bambuddy filament and Homebox material stock. A note's own value
  always wins over a synced one.
- PersonalReader: updates only Library notes with a matching anilistId,
  changes to Greg's notes are held for review; Reading series with no note
  show as suggestions on the admin Overview.
- /api/inquiries and /api/orders: Turnstile, rate limits, a saved copy in the
  content service (intake token) plus email over SMTP. Orders are re-checked
  against the live notes: accepted only when the category's ordersOpen is
  true and the line has capacity.
- Admin Inbox for saved submissions. Options' inStock is optional so synced
  stock can fill it. All settings from process.env; .env.example per service.
- Sources could not be reached from the build environment; parsers are tested
  against fixtures labelled as not live.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012aSbo2D1qP8cMFQCykf7kx

services/site/package.json

@@ -16,6 +16,7 @@
     "@gk/ui": "*",
     "astro": "7.3.5",
     "marked": "18.0.14",
+    "nodemailer": "10.0.10",
     "pdf-lib": "^1.17.1",
     "pdfkit": "^0.20.2"
   },