fix(chv): CHV 54 VmConfig 形态——payload.kernel/cmdline 纯字符串 + 磁盘显式 image_type Raw

真机 CHV 54.0.0 实测：旧顶层 kernel:{path}/cmdline:{args}
create 时 204 照放、vm.boot 400 'No bootitem provided'；
补 payload 后又报 'Image type required for disk'（raw 盘
无魔数、探测失败），磁盘须显式 image_type，枚举原名
Raw（JSON 写小写 raw 报 unknown variant）。

cloud/tests/test_cloud_hypervisor.py

@@ -243,9 +243,10 @@ class ConfigCommandTest(ChvCase):
         self.assertEqual(cfg["cpus"], {"boot_vcpus": 2,
                                        "max_vcpus": 2})
         self.assertEqual(cfg["memory"]["size"], 2 * 1024 ** 3)
-        self.assertEqual(cfg["kernel"]["path"], self.kernel)
-        self.assertEqual(cfg["disks"], [{"path": disk}])
-        self.assertEqual(cfg["cmdline"]["args"],
+        self.assertEqual(cfg["payload"]["kernel"], self.kernel)
+        self.assertEqual(cfg["disks"],
+                         [{"path": disk, "image_type": "Raw"}])
+        self.assertEqual(cfg["payload"]["cmdline"],
                          "console=hvc0 root=/dev/vda1 rw")
 
     def test_memory_parsing(self):
@@ -346,7 +347,10 @@ class WakeApiTest(ChvCase):
         self.assertEqual(kinds[1], ("PUT", "/vm.create"))
         self.assertEqual(kinds[2], ("PUT", "/vm.boot"))
         create_payload = self.api_calls[1][2]
-        self.assertEqual(create_payload["kernel"]["path"], self.kernel)
+        # CHV 54：内核走 payload.kernel 纯字符串（旧顶层
+        # kernel:{path} 会被忽略、vm.boot 400）。
+        self.assertEqual(create_payload["payload"]["kernel"], self.kernel)
+        self.assertEqual(create_payload["disks"][0]["image_type"], "Raw")
         self.assertTrue(create_payload["disks"][0]["path"].endswith(
             "disk.raw"))
         events = [e for e, _, _, _ in self.audit]