feat(chv-guest): 阶段 1 数据盘独立持久（客内挂载）

- 新增 chv-guest/chv-data-mount.sh：按 LABEL=CHVDATA 找盘
  （不依赖 /dev/vd? 固定名；seed ISO 与根盘排除），无 fs
  即 mkfs.ext4 -L CHVDATA，挂到 /home/chv/workspace，幂等；
  无数据盘即静默退出 0（copy 模式旧 VM 不报错）。
- build.sh：缺脚本即失败（与 chv-sync.sh 同款门）；拷入
  镜像 /usr/local/bin/chv-data-mount；99-chv-sync.cfg
  runcmd 在 chv-sync boot 之前调它（工作区先挂好再 clone）。
- buildinfo.py BASE_CONTENTS 与两 lockfile DECLARED_SOURCES
  登记 chv-data-mount（repo_commit，随 P2 三脚本先例）。
- tests：test_chv_opt_stage1.DataMountScriptTest（脚本内容、
  构建接线、lockfile 登记）；P2 干跑夹具补新文件。
回归：discover test_chv_*.py 与 test_cloud_hypervisor.py 全过。
不推、不合、不部署；只本地分支。

cloud/tests/test_chv_muse_p2.py

@@ -568,7 +568,8 @@ class BuildDryRunTest(unittest.TestCase):
             os.makedirs(os.path.join(bindir, "codex-resources"))
             for name in ("build.sh", "buildinfo.py", "check_lockfile.py",
                          "generate_lockfile.py", "chv-sync.sh",
-                         "chv-cell.py", "chv-broker.py", "chv-browser.py"):
+                         "chv-cell.py", "chv-broker.py", "chv-browser.py",
+                         "chv-data-mount.sh"):
                 shutil.copy2(ROOT / "chv-guest" / name,
                              os.path.join(guest, name))
             shutil.copy2(ROOT / "host.py", os.path.join(repo, "host.py"))

cloud/tests/test_chv_opt_stage1.py

@@ -653,5 +653,55 @@ class PersistentPoolTest(ChvOpt1Case):
         self.assertEqual(len(self.launches), 1)
 
 
+# -- 数据盘挂载脚本与构建接线 ----------------------------------------------
+class DataMountScriptTest(unittest.TestCase):
+    def _repo(self, *parts):
+        return os.path.join(
+            Path(__file__).resolve().parents[2], *parts)
+
+    def test_mount_script_present_and_safe(self):
+        path = self._repo("chv-guest", "chv-data-mount.sh")
+        with open(path) as fh:
+            text = fh.read()
+        self.assertIn("LABEL=CHVDATA", text)
+        self.assertIn("/home/chv/workspace", text)
+        self.assertIn("mkfs.ext4", text)
+        # 无数据盘即静默退出 0，不挡启动；绝不含任何秘密值。
+        self.assertIn("no data disk found, skip", text)
+        for secret in ("GITEA_TOKEN", "sk-", "password"):
+            self.assertNotIn(secret, text)
+
+    def test_build_sh_wires_mount_script(self):
+        with open(self._repo("chv-guest", "build.sh")) as fh:
+            text = fh.read()
+        self.assertIn("chv-data-mount.sh:/usr/local/bin/", text)
+        self.assertIn("chv-data-mount >>/var/log/chv-data-mount.log",
+                      text)
+        # 挂载在 chv-sync boot 之前（工作区须先挂好再 clone）：
+        # 以 99-chv-sync.cfg 那一行为准（文件头注释里也出现
+        # chv-sync boot 字样，不能全文 index 比对）。
+        cfg_line = next(
+            line for line in text.splitlines()
+            if "99-chv-sync.cfg" in line and "runcmd" in line)
+        self.assertLess(cfg_line.index("chv-data-mount >>"),
+                        cfg_line.index("chv-sync boot"))
+
+    def test_lockfile_declares_mount_script(self):
+        import importlib.util
+        guest = self._repo("chv-guest")
+        spec = importlib.util.spec_from_file_location(
+            "stage1_buildinfo", os.path.join(guest, "buildinfo.py"))
+        buildinfo = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(buildinfo)
+        self.assertIn("chv-data-mount", buildinfo.BASE_CONTENTS)
+        for name in ("check_lockfile.py", "generate_lockfile.py"):
+            spec = importlib.util.spec_from_file_location(
+                "stage1_" + name[:-3], os.path.join(guest, name))
+            mod = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(mod)
+            self.assertEqual(mod.DECLARED_SOURCES["chv-data-mount"],
+                             "repo_commit")
+
+
 if __name__ == "__main__":
     unittest.main()