[配置]：完成 .env 文件读取配置，包含自动加载、CLI 参数、测试覆盖和中文说明

tests/test_cli_acceptance.py

@@ -27,6 +27,19 @@ class CliAcceptanceTests(unittest.TestCase):
         self.assertEqual(code, 0)
         self.assertTrue(data["valid"])
 
+    def test_show_config_reads_env_file_without_printing_secret(self) -> None:
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as tmp:
+            path = f"{tmp}/.env"
+            with open(path, "w", encoding="utf-8") as handle:
+                handle.write("OWNER_LLM_API_KEY=secret-value\nOWNER_LLM_MODEL=file-model\n")
+            code, data = self.call("--env-file", path, "--show-config")
+        self.assertEqual(code, 0)
+        self.assertTrue(data["llm_api_key_present"])
+        self.assertEqual(data["llm_model"], "file-model")
+        self.assertNotIn("secret-value", str(data))
+
     def test_security_check_command_has_no_leaks(self) -> None:
         code, data = self.call("security-check")
         self.assertEqual(code, 0)