🐛 fix(config-secret-storage): 修复密文编辑与状态残留问题

- 修复自定义连接编辑时已保存 DSN 无法留空沿用的问题
- 重置 AI 供应商编辑态与清空密钥开关，避免关闭后状态残留
- 对齐浏览器 mock 复制连接的 config.id 语义并补充回归测试

frontend/src/utils/aiProviderEditorState.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  buildAddProviderEditorSession,
+  buildClosedProviderEditorSession,
+  buildEditProviderEditorSession,
+} from './aiProviderEditorState';
+
+describe('aiProviderEditorState', () => {
+  it('resets clearProviderSecret when starting add flow', () => {
+    const session = buildAddProviderEditorSession({
+      previousClearProviderSecret: true,
+      presetBackendType: 'openai',
+      presetBaseUrl: 'https://api.openai.com/v1',
+      presetModel: 'gpt-4.1',
+    });
+
+    expect(session.clearProviderSecret).toBe(false);
+    expect(session.isEditing).toBe(true);
+    expect(session.testStatus).toBe('idle');
+  });
+
+  it('resets clearProviderSecret when starting edit flow', () => {
+    const session = buildEditProviderEditorSession({
+      previousClearProviderSecret: true,
+      provider: {
+        id: 'provider-1',
+        type: 'openai',
+        name: 'OpenAI',
+        apiKey: '',
+        hasSecret: true,
+      },
+    });
+
+    expect(session.clearProviderSecret).toBe(false);
+    expect(session.isEditing).toBe(true);
+    expect(session.editingProvider?.id).toBe('provider-1');
+  });
+
+  it('resets clearProviderSecret when the modal closes', () => {
+    const session = buildClosedProviderEditorSession({
+      previousClearProviderSecret: true,
+    });
+
+    expect(session.clearProviderSecret).toBe(false);
+    expect(session.isEditing).toBe(false);
+    expect(session.editingProvider).toBeNull();
+  });
+});