feat(indexer,backoffice): ajouter warnings dans les stats de job, skip fichiers inaccessibles

- Indexer: ajout du champ `warnings` dans JobStats pour les erreurs
  non-fatales (fichiers inaccessibles, permissions)
- Indexer: skip les fichiers dont le stat échoue au lieu de faire
  crasher tout le scan de la library
- Backoffice: affichage des warnings dans le détail job (summary,
  timeline, Index Statistics) et dans la popin jobs

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

apps/backoffice/app/components/JobsIndicator.tsx

@@ -19,6 +19,7 @@ interface Job {
     scanned_files: number;
     indexed_files: number;
     errors: number;
+    warnings: number;
   } | null;
 }
 
@@ -261,8 +262,11 @@ export function JobsIndicator() {
                         {job.stats_json && (
                           <div className="flex items-center gap-3 mt-1.5 text-xs text-muted-foreground">
                             <span>✓ {job.stats_json.indexed_files}</span>
+                            {(job.stats_json.warnings ?? 0) > 0 && (
+                              <span className="text-warning">⚠ {job.stats_json.warnings}</span>
+                            )}
                             {job.stats_json.errors > 0 && (
-                              <span className="text-destructive">⚠ {job.stats_json.errors}</span>
+                              <span className="text-destructive">✕ {job.stats_json.errors}</span>
                             )}
                           </div>
                         )}

apps/backoffice/app/jobs/[id]/page.tsx

@@ -30,6 +30,7 @@ interface JobDetails {
     indexed_files: number;
     removed_files: number;
     errors: number;
+    warnings: number;
   } | null;
   error_opt: string | null;
 }
@@ -182,6 +183,7 @@ export default async function JobDetailPage({ params }: JobDetailPageProps) {
               <span className="ml-2 text-success/80">
                 — {job.stats_json.scanned_files} scanned, {job.stats_json.indexed_files} indexed
                 {job.stats_json.removed_files > 0 && `, ${job.stats_json.removed_files} removed`}
+                {(job.stats_json.warnings ?? 0) > 0 && `, ${job.stats_json.warnings} warnings`}
                 {job.stats_json.errors > 0 && `, ${job.stats_json.errors} errors`}
                 {job.total_files != null && job.total_files > 0 && `, ${job.total_files} thumbnails`}
               </span>
@@ -312,6 +314,7 @@ export default async function JobDetailPage({ params }: JobDetailPageProps) {
                           <span className="text-muted-foreground font-normal ml-1">
                             · {job.stats_json.scanned_files} scanned, {job.stats_json.indexed_files} indexed
                             {job.stats_json.removed_files > 0 && `, ${job.stats_json.removed_files} removed`}
+                            {(job.stats_json.warnings ?? 0) > 0 && `, ${job.stats_json.warnings} warn`}
                           </span>
                         )}
                       </p>
@@ -462,10 +465,11 @@ export default async function JobDetailPage({ params }: JobDetailPageProps) {
               )}
             </CardHeader>
             <CardContent>
-              <div className="grid grid-cols-2 sm:grid-cols-4 gap-4">
+              <div className="grid grid-cols-2 sm:grid-cols-5 gap-4">
                 <StatBox value={job.stats_json.scanned_files} label="Scanned" variant="success" />
                 <StatBox value={job.stats_json.indexed_files} label="Indexed" variant="primary" />
                 <StatBox value={job.stats_json.removed_files} label="Removed" variant="warning" />
+                <StatBox value={job.stats_json.warnings ?? 0} label="Warnings" variant={(job.stats_json.warnings ?? 0) > 0 ? "warning" : "default"} />
                 <StatBox value={job.stats_json.errors} label="Errors" variant={job.stats_json.errors > 0 ? "error" : "default"} />
               </div>
             </CardContent>