fix(classifieds): manual cleanup of related rows before delete

SQLAlchemy ORM tries to UPDATE classified_reads.classified_id = NULL
before deleting the classifieds row, even though the FK has ON DELETE
CASCADE at DB level. The NOT NULL constraint on classified_id then
raises IntegrityError. Same pattern as the forum_reply_reads fix from
2026-02. Manually delete reads, interests, questions, attachments
before db.delete(classified).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

blueprints/community/classifieds/routes.py

@@ -409,6 +409,14 @@ def delete(classified_id):
         if not classified:
             return jsonify({'success': False, 'error': 'Ogłoszenie nie istnieje'}), 404
 
+        # SQLAlchemy ORM doesn't honor DB-level CASCADE — it tries to UPDATE
+        # FK to NULL on related rows first, which fails on NOT NULL columns.
+        # Same pattern as forum reply delete fix. Wipe related rows first.
+        db.query(ClassifiedRead).filter(ClassifiedRead.classified_id == classified.id).delete(synchronize_session=False)
+        db.query(ClassifiedInterest).filter(ClassifiedInterest.classified_id == classified.id).delete(synchronize_session=False)
+        db.query(ClassifiedQuestion).filter(ClassifiedQuestion.classified_id == classified.id).delete(synchronize_session=False)
+        db.query(ClassifiedAttachment).filter(ClassifiedAttachment.classified_id == classified.id).delete(synchronize_session=False)
+
         db.delete(classified)
         db.commit()