fix(indexer): full_rebuild par library ne supprime plus les thumbnails des autres libraries

cleanup_orphaned_thumbnails chargeait uniquement les book IDs de la library
en cours de rebuild, considérant les thumbnails des autres libraries comme
orphelins et les supprimant. La fonction charge désormais tous les book IDs
toutes libraries confondues.

Ajout d'un test de régression dans infra/smoke.sh qui vérifie que le
full_rebuild d'une library ne réduit pas le nombre de thumbnails des autres.

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

apps/indexer/src/analyzer.rs

@@ -388,16 +388,14 @@ pub async fn regenerate_thumbnails(
 }
 
 /// Delete orphaned thumbnail files (books deleted in full_rebuild get new UUIDs).
-pub async fn cleanup_orphaned_thumbnails(
-    state: &AppState,
-    library_id: Option<Uuid>,
-) -> Result<()> {
+pub async fn cleanup_orphaned_thumbnails(state: &AppState) -> Result<()> {
     let config = load_thumbnail_config(&state.pool).await;
 
+    // Load ALL book IDs across all libraries — we need the complete set to avoid
+    // deleting thumbnails that belong to other libraries during a per-library rebuild.
     let existing_book_ids: std::collections::HashSet<Uuid> = sqlx::query_scalar(
-        r#"SELECT id FROM books WHERE (library_id = $1 OR $1 IS NULL)"#,
+        r#"SELECT id FROM books"#,
     )
-    .bind(library_id)
     .fetch_all(&state.pool)
     .await
     .unwrap_or_default()