fix(maker): l'editor task si riallinea al copy-on-write invece di 409 (#4)

Dopo il copy-on-write del backend (modifica su versione con misure ->
nuovi id per task e quote), task_editor.html teneva in memoria gli id
vecchi: il salvataggio successivo riceveva 409 "Cannot modify a
non-current version". Ogni handler di salvataggio (create/update/delete
di task e quote, reorder, upload immagine) ora ricarica la pagina su
409, mostrando un avviso dopo il reload. updateTask/updateSubtask/
addSubtask ricaricano anche su successo se l'id restituito (recipe_id
task, task_id quota) non corrisponde a quello locale - il copy-on-write
avvenuto silenziosamente.

Stringa aggiunta ai due cataloghi .po. Test: proxy Flask che verifica
il passaggio del 409 (test_maker.py), sintassi JS dello script inline
di task_editor.html con node --check (test_template_js_syntax.py).

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

src/frontend/flask_app/tests/test_maker.py

@@ -121,3 +121,43 @@ class TestRecipeEdit:
         resp = logged_in_client.get("/maker/recipes/999/edit", follow_redirects=False)
         assert resp.status_code == 302
         assert "/maker/recipes" in resp.headers["Location"]
+
+
+class TestVersionConflictProxy:
+    """gitea#4: a 409 from the backend (edit targeting a non-current version,
+    left behind by an earlier copy-on-write) must reach the browser as a 409 -
+    task_editor.html's _reloadForNewVersion() only triggers on that status.
+    """
+
+    _CONFLICT = {
+        "error": True,
+        "status_code": 409,
+        "detail": "Cannot modify a non-current version. Create a new version first.",
+    }
+
+    def test_update_task_proxies_409(self, logged_in_client, mock_api_client):
+        mock_api_client.put.return_value = self._CONFLICT
+
+        resp = logged_in_client.put("/maker/api/tasks/11", json={"title": "x"})
+
+        assert resp.status_code == 409
+        assert resp.get_json()["detail"] == self._CONFLICT["detail"]
+
+    def test_update_subtask_proxies_409(self, logged_in_client, mock_api_client):
+        mock_api_client.put.return_value = self._CONFLICT
+
+        resp = logged_in_client.put("/maker/api/subtasks/21", json={"nominal": 1.0})
+
+        assert resp.status_code == 409
+        assert resp.get_json()["detail"] == self._CONFLICT["detail"]
+
+    def test_create_subtask_proxies_409(self, logged_in_client, mock_api_client):
+        mock_api_client.post.return_value = self._CONFLICT
+
+        resp = logged_in_client.post(
+            "/maker/api/tasks/11/subtasks",
+            json={"marker_number": 1, "description": "x"},
+        )
+
+        assert resp.status_code == 409
+        assert resp.get_json()["detail"] == self._CONFLICT["detail"]