test: 建立单元测试基座

- 新增 unittest tests 基座，覆盖 appconfig 与 db 纯逻辑

- 增加 excel/prompts 未实现模块的契约占位测试

- 补强 config.json 对 *_token 与 *_password 的敏感字段拦截

- 更新任务看板、当前状态、API 合约和进度记录

tests/test_module_contracts.py

@@ -0,0 +1,43 @@
+import importlib
+import importlib.util
+import os
+import sys
+import unittest
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+from _helpers import REPO_ROOT
+
+if str(REPO_ROOT) not in sys.path:
+    sys.path.insert(0, str(REPO_ROOT))
+
+
+def import_or_skip(module_name):
+    if importlib.util.find_spec(module_name) is None:
+        raise unittest.SkipTest(f"{module_name} 尚未实现")
+    return importlib.import_module(module_name)
+
+
+class PendingModuleContractTests(unittest.TestCase):
+    def test_excel_contract_when_module_exists(self):
+        excel = import_or_skip("app.excel")
+        for name in ("import_tasks", "match_summary", "write_back", "export_copy"):
+            self.assertTrue(callable(getattr(excel, name, None)), name)
+
+    def test_prompts_contract_when_module_exists(self):
+        prompts = import_or_skip("app.prompts")
+        for name in (
+            "load_title_prompt",
+            "save_title_prompt",
+            "list_cover_templates",
+            "load_cover_template",
+            "save_cover_template",
+            "rename_cover_template",
+            "delete_cover_template",
+            "render_prompt",
+        ):
+            self.assertTrue(callable(getattr(prompts, name, None)), name)
+
+
+if __name__ == "__main__":
+    unittest.main()