feat(flutter): 增加 debug 服务地址编辑器

test/config/server_endpoint_test.dart

@@ -113,6 +113,22 @@ void main() {
     expect(AppConfig.apiBaseUrl, AppConfig.devHostBaseUrl);
   });
 
+  test('should_probe_explicit_runtime_endpoint_first', () async {
+    const custom = 'http://custom.test:8081';
+    final attempts = <String>[];
+    AppConfig.applyRuntimeBaseUrl(custom);
+
+    await AppConfig.probeAndApplyBaseUrl(
+      probe: (baseUrl) async {
+        attempts.add(baseUrl);
+        return baseUrl == custom;
+      },
+    );
+
+    expect(attempts, [custom]);
+    expect(AppConfig.apiBaseUrl, custom);
+  });
+
   test('should_apply_stored_url_only_when_debug_is_enabled', () async {
     SharedPreferencesAsyncPlatform.instance =
         InMemorySharedPreferencesAsync.withData({
@@ -139,6 +155,7 @@ void main() {
       await SharedPreferencesAsync().getString(ServerEndpoint.preferenceKey),
       'http://192.168.31.187:8081',
     );
+    expect(AppConfig.apiBaseUrl, 'http://192.168.31.187:8081');
 
     await ServerEndpoint.clear();
     expect(