fix: plusieurs correctifs jobs et analyzer

- cancel_job: ajouter 'extracting_pages' aux statuts annulables
- cleanup_stale_jobs: couvrir 'extracting_pages' et 'generating_thumbnails' au redémarrage
- analyzer: ne pas régénérer le thumbnail si déjà existant (skip sub-phase B)
- analyzer: supprimer les dotfiles macOS (._*) encore en DB
- SSE backoffice: réduire le spam de logs en cas d'API injoignable

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

apps/indexer/src/job.rs

@@ -13,7 +13,7 @@ pub async fn cleanup_stale_jobs(pool: &PgPool) -> Result<()> {
         SET status = 'failed',
             finished_at = NOW(),
             error_opt = 'Job interrupted by indexer restart'
-        WHERE status = 'running'
+        WHERE status IN ('running', 'extracting_pages', 'generating_thumbnails')
           AND started_at < NOW() - INTERVAL '5 minutes'
         RETURNING id
         "#,