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/FolderPicker.tsx

@@ -27,7 +27,7 @@ export function FolderPicker({ initialFolders, selectedPath, onSelect }: FolderP
           <input
             type="text"
             readOnly
-            value={selectedPath || "Select a folder..."}
+            value={selectedPath || "Sélectionner un dossier..."}
             className={`
               w-full px-3 py-2 rounded-lg border bg-card
               text-sm font-mono
@@ -57,7 +57,7 @@ export function FolderPicker({ initialFolders, selectedPath, onSelect }: FolderP
           <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
             <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 7v10a2 2 0 002 2h14a2 2 0 002-2V9a2 2 0 00-2-2h-6l-2-2H5a2 2 0 00-2 2z" />
           </svg>
-          Browse
+          Parcourir
         </Button>
       </div>
 
@@ -79,7 +79,7 @@ export function FolderPicker({ initialFolders, selectedPath, onSelect }: FolderP
                   <svg className="w-5 h-5 text-primary" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                     <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 7v10a2 2 0 002 2h14a2 2 0 002-2V9a2 2 0 00-2-2h-6l-2-2H5a2 2 0 00-2 2z" />
                   </svg>
-                  <span className="font-medium">Select Folder</span>
+                  <span className="font-medium">Sélectionner le dossier</span>
                 </div>
                 <button
                   type="button"
@@ -104,7 +104,7 @@ export function FolderPicker({ initialFolders, selectedPath, onSelect }: FolderP
               {/* Footer */}
               <div className="flex items-center justify-between px-4 py-3 border-t border-border/50 bg-muted/30">
                 <span className="text-xs text-muted-foreground">
-                  Click a folder to select it
+                  Cliquez sur un dossier pour le sélectionner
                 </span>
                 <div className="flex gap-2">
                   <Button
@@ -113,7 +113,7 @@ export function FolderPicker({ initialFolders, selectedPath, onSelect }: FolderP
                     size="sm"
                     onClick={() => setIsOpen(false)}
                   >
-                    Cancel
+                    Annuler
                   </Button>
                 </div>
               </div>