fix(ai): clarify config save feedback and model selection

tests/test_assistant_api.py

@@ -71,6 +71,7 @@ def test_model_intent_polls_in_progress_and_retries_invalid_response(workspace,
             polled["posts"] += 1
             # 第一次 POST 返回损坏文本（触发整体重试），第二次 POST 返回 in_progress
             if polled["posts"] == 1:
+
                 class Bad:
                     def raise_for_status(self):
                         return None
@@ -87,7 +88,9 @@ def test_model_intent_polls_in_progress_and_retries_invalid_response(workspace,
         def get(self, *args, **kwargs):
             polled["n"] += 1
             assert args[0].endswith("/responses/resp-1")
-            return completed_response({"action": "anomalies", "metric": "revenue", "group": "department", "filters": []})
+            return completed_response(
+                {"action": "anomalies", "metric": "revenue", "group": "department", "filters": []}
+            )
 
     with patch("finance.assistant.httpx.Client", ClientMock):
         intent = model_intent("看异常", ds, {"metric": "revenue", "group": "department", "filters": {}})
@@ -152,6 +155,34 @@ def test_ai_config_requires_full_admin_and_masks_key(workspace):
     assert Audit.objects.filter(action="ai_config.update").exists()
 
 
+def test_ai_config_save_returns_saved_config_and_preserves_masked_key(workspace):
+    ds, _, client, _, _ = workspace
+    payload = {
+        "enabled": True,
+        "provider": "local",
+        "base_url": "http://127.0.0.1:11434/v1/",
+        "api_key": "saved-config-test-secret",
+        "model": "qwen2.5:7b",
+    }
+
+    for api_key, model in [(payload["api_key"], "qwen2.5:7b"), ("", "llama3.1:8b")]:
+        payload.update(api_key=api_key, model=model)
+        response = client.put("/api/ai-config", data=payload, content_type="application/json")
+        assert response.status_code == 200
+        saved = response.json()
+        shown = client.get("/api/ai-config").json()
+        assert saved == {"ok": True, **shown}
+        assert saved["enabled"] is True
+        assert saved["provider"] == "local"
+        assert saved["base_url"] == "http://127.0.0.1:11434/v1"
+        assert saved["model"] == model
+        assert saved["api_key_set"] is True
+        assert saved["updated_at"]
+        assert "api_key" not in saved
+        assert "saved-config-test-secret" not in response.content.decode()
+        assert AIConfig.objects.get(organization=ds.organization).api_key == "saved-config-test-secret"
+
+
 def test_ai_models_lists_local_models(workspace):
     ds, _, client, _, _ = workspace
     client.put(