feat: add job runs chart and scrollable reading lists on dashboard

- Add multi-line chart showing job runs over time by type (scan,
  rebuild, thumbnails, other) with the same day/week/month toggle
- Limit currently reading and recently read lists to 3 visible items
  with a scrollbar for overflow
- Fix NUMERIC→BIGINT cast for SUM/COALESCE in jobs SQL queries

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/backoffice/lib/i18n/fr.ts

@@ -69,6 +69,11 @@ const fr = {
   "dashboard.byFormat": "Par format",
   "dashboard.byLibrary": "Par bibliothèque",
   "dashboard.booksAdded": "Livres ajoutés",
+  "dashboard.jobsOverTime": "Exécutions de jobs",
+  "dashboard.jobScan": "Scan",
+  "dashboard.jobRebuild": "Rebuild",
+  "dashboard.jobThumbnail": "Thumbnails",
+  "dashboard.jobOther": "Autre",
   "dashboard.periodDay": "Jour",
   "dashboard.periodWeek": "Semaine",
   "dashboard.periodMonth": "Mois",