List favorites newest first

GET /image/favorites had no ORDER BY, so SQLite returned rows in index
order (by path). Order by id descending so the app's Favorites view
(FileViewer #73) shows what was just added on top.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/database/mod.rs

@@ -364,8 +364,10 @@ impl FavoriteDao for SqliteFavoriteDao {
     fn get_favorites(&mut self, user_id: i32) -> Result<Vec<Favorite>, DbError> {
         use schema::favorites::dsl::*;
 
+        // Newest first, so a Favorites view lists what was just added on top.
         favorites
             .filter(userid.eq(user_id))
+            .order(id.desc())
             .load::<Favorite>(self.connection.lock().unwrap().deref_mut())
             .map_err(|e| DbError::log(DbErrorKind::QueryError, e))
     }
@@ -3456,3 +3458,30 @@ mod exif_dao_tests {
         );
     }
 }
+
+#[cfg(test)]
+mod favorite_dao_tests {
+    use super::*;
+    use crate::database::test::in_memory_db_connection;
+
+    #[test]
+    fn favorites_list_newest_first() {
+        let mut dao =
+            SqliteFavoriteDao::from_shared(Arc::new(Mutex::new(in_memory_db_connection())));
+        for p in ["b.jpg", "c.jpg", "a.jpg"] {
+            dao.add_favorite(1, p).unwrap();
+        }
+        dao.add_favorite(2, "z.jpg").unwrap();
+        let paths: Vec<String> = dao
+            .get_favorites(1)
+            .unwrap()
+            .into_iter()
+            .map(|f| f.path)
+            .collect();
+        assert_eq!(
+            paths,
+            ["a.jpg", "c.jpg", "b.jpg"],
+            "insertion order, newest first; per user"
+        );
+    }
+}