Fix model-controller mismatches and routing issues

- ticket: add user_id, priority, category fields; fix _serialize_ticket -> _serialize
- package: fix is_active -> active (Odoo auto-filter), remove invalid entity_id filter
- walkthrough: add sequence field; fix controller to use name/content instead of title/steps
- users: fix encoach_user_type -> encoach_type, encoach_entity_id -> entity_rel_ids.entity_id
- generation: use EncoachGenerationService class instead of nonexistent ORM model,
  fix /api/exam/level/ route conflict (separate GET and POST URLs)

Made-with: Cursor

encoach_api/controllers/subscriptions.py

@@ -19,10 +19,7 @@ class SubscriptionsController(EncoachMixin, http.Controller):
             if not user:
                 return self._error_response('Unauthorized', 401)
 
-            domain = [('is_active', '=', True)]
-            entity_id = kwargs.get('entityID')
-            if entity_id:
-                domain.append(('entity_id', '=', int(entity_id)))
+            domain = []
 
             packages = request.env['encoach.package'].sudo().search(domain, order='price asc')
             return self._json_response([p.to_encoach_dict() for p in packages])