feat(ai): enforce direct image edit contract

tests/test_ai.py

@@ -69,10 +69,10 @@ class AITests(TempDirMixin, unittest.TestCase):
             "name": "Image",
             "category": "image",
             "enabled": True,
-            "url": "https://example.invalid/v1/chat/completions",
+            "url": "https://example.invalid/v1",
             "model": "image-model",
             "api_key": "sk-image-secret",
-            "api_type": "auto",
+            "api_type": "images_edits",
             "connect_timeout_seconds": 1,
             "timeout_seconds": 1,
             "extra_body": {},
@@ -378,9 +378,13 @@ class AITests(TempDirMixin, unittest.TestCase):
             b64_image = base64.b64encode(generated.getvalue()).decode("ascii")
 
             def fake_urlopen(request, timeout=None):
-                body = json.loads(request.data.decode("utf-8"))
-                self.assertEqual("image-model", body["model"])
-                self.assertIn("目标分辨率：512", body["messages"][0]["content"][0]["text"])
+                body = request.data
+                self.assertIn(b'name="model"', body)
+                self.assertIn(b"image-model", body)
+                self.assertIn(b'name="image[]"', body)
+                self.assertIn(b'name="n"', body)
+                self.assertIn(b"\r\n1\r\n", body)
+                self.assertIn("multipart/form-data", request.headers["Content-type"])
                 return _Response({"data": [{"b64_json": b64_image}]})
 
             with mock.patch("app.ai.urllib.request.urlopen", side_effect=fake_urlopen):
@@ -399,6 +403,44 @@ class AITests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_image_edit_body_keeps_repeated_image_fields_in_order(self):
+        with self.make_temp_dir() as temp_dir:
+            first = os.path.join(temp_dir, "primary.jpg")
+            second = os.path.join(temp_dir, "reference.png")
+            with open(first, "wb") as fh:
+                fh.write(b"first-image")
+            with open(second, "wb") as fh:
+                fh.write(b"second-image")
+
+            body, content_type = ai._image_edit_body(
+                {"model": "image-model", "extra_body": {"quality": "high"}},
+                "生成商品图",
+                [first, second],
+                "1k",
+            )
+
+            self.assertIn("multipart/form-data", content_type)
+            self.assertEqual(2, body.count(b'name="image[]"'))
+            self.assertLess(body.index(b"primary.jpg"), body.index(b"reference.png"))
+            self.assertIn(b'name="n"', body)
+            self.assertIn(b"\r\n1\r\n", body)
+
+        self.assert_removed(temp_dir)
+
+    def test_direct_image_response_only_accepts_openai_data_fields(self):
+        encoded = base64.b64encode(b"image-bytes").decode("ascii")
+
+        self.assertEqual(encoded, ai._find_image_ref({"data": [{"b64_json": encoded}]}))
+        self.assertEqual(
+            "https://images.example.com/new.png",
+            ai._find_image_ref({"data": [{"url": "https://images.example.com/new.png"}]}),
+        )
+        self.assertIsNone(ai._find_image_ref({"choices": [{"image_url": "x"}]}))
+        with self.assertRaisesRegex(ai.AIError, "OpenAI 图片编辑接口"):
+            ai._extract_image_bytes({"message": {"url": "https://bad.example/x"}}, {}, {})
+        with self.assertRaisesRegex(ai.AIError, "只允许 http/https"):
+            ai._extract_image_bytes({"data": [{"url": "file:///tmp/image.png"}]}, {}, {})
+
     def test_cmhub_gen_title_uses_alias_and_emits_metadata(self):
         with self.make_temp_dir() as temp_dir:
             cfg, key_path = self._cmhub_config(temp_dir)