Fix remove/mark-watched not working on common-list movies

getLists() returned the common list via MAX(id) grouped across both
users' rows, so the id handed back could belong to either partner.
remove()/markWatched() scope by (id, user_id), so whenever it picked
the partner's id, the query silently matched zero rows while still
reporting success.

Now each user's own is_common=1 rows are returned directly, so the id
is always theirs. Also fixes the frontend never recognizing common
movies as "already added" (see watchgether-web).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

models/Movie.php

@@ -63,13 +63,11 @@ class Movie {
         }
 
         // 3. Commune
-        $stmt = $this->db->prepare("
-            SELECT MAX(id) as id, tmdb_id, title, poster_path, media_type, is_common, MAX(added_at) as added_at 
-            FROM movies 
-            WHERE is_common = 1 AND (user_id = ? OR user_id = ?)
-            GROUP BY tmdb_id, title, poster_path, media_type, is_common
-        ");
-        $stmt->execute([$myId, $partnerId]);
+        // On renvoie MA propre ligne (pas une fusion avec celle du/de la partenaire) :
+        // chacun a sa propre ligne is_common=1 pour le même film, et remove/mark-watched
+        // ont besoin de MON id pour agir sur MA ligne, pas une autre.
+        $stmt = $this->db->prepare("SELECT * FROM movies WHERE user_id = ? AND is_common = 1 ORDER BY added_at DESC");
+        $stmt->execute([$myId]);
         $common = $stmt->fetchAll(PDO::FETCH_ASSOC);
 
         return ["perso" => $perso, "partner" => $partner, "common" => $common];