feat: add batch metadata jobs, series filters, and translate backoffice to French

- Add metadata_batch job type with background processing via tokio::spawn
- Auto-apply metadata only when single result at 100% confidence
- Support primary + fallback provider per library, "none" to opt out
- Add batch report/results API endpoints and job detail UI
- Add series_status and has_missing filters to both series listing pages
- Add GET /series/statuses endpoint for dynamic filter options
- Normalize series_metadata status values (migration 0036)
- Hide ComicVine provider tab when no API key configured
- Translate entire backoffice UI from English to French

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

apps/backoffice/app/components/ui/Badge.tsx

@@ -71,8 +71,8 @@ const statusVariants: Record<string, BadgeVariant> = {
 };
 
 const statusLabels: Record<string, string> = {
-  extracting_pages: "Extracting pages",
-  generating_thumbnails: "Thumbnails",
+  extracting_pages: "Extraction des pages",
+  generating_thumbnails: "Miniatures",
 };
 
 interface StatusBadgeProps {
@@ -96,10 +96,10 @@ const jobTypeVariants: Record<string, BadgeVariant> = {
 };
 
 const jobTypeLabels: Record<string, string> = {
-  rebuild: "Index",
-  full_rebuild: "Full Index",
-  thumbnail_rebuild: "Thumbnails",
-  thumbnail_regenerate: "Regen. Thumbnails",
+  rebuild: "Indexation",
+  full_rebuild: "Indexation complète",
+  thumbnail_rebuild: "Miniatures",
+  thumbnail_regenerate: "Régén. miniatures",
   cbr_to_cbz: "CBR → CBZ",
 };