✨ feat(security): 完成配置密文存储前后端闭环

- 补齐连接与代理密文字段的保留替换清空语义

- 接通保存复制删除导入接口并返回 secretless 视图

- 刷新 Wails 绑定并补充实现留痕文档

frontend/src/utils/connectionSecretDraft.test.ts

@@ -0,0 +1,86 @@
+import { describe, expect, it } from 'vitest';
+
+import { resolveConnectionSecretDraft } from './connectionSecretDraft';
+
+describe('resolveConnectionSecretDraft', () => {
+  it('keeps an existing stored secret when edit form leaves the field blank', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: true,
+      valueInput: '',
+      clearSecret: false,
+    });
+
+    expect(result.value).toBe('');
+    expect(result.clearStoredSecret).toBe(false);
+    expect(result.keepsStoredSecret).toBe(true);
+    expect(result.hasSecretAfterSave).toBe(true);
+  });
+
+  it('replaces the stored secret when a new value is entered', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: true,
+      valueInput: '  mongodb://demo  ',
+      clearSecret: false,
+      trimInput: true,
+    });
+
+    expect(result.value).toBe('mongodb://demo');
+    expect(result.clearStoredSecret).toBe(false);
+    expect(result.keepsStoredSecret).toBe(false);
+    expect(result.hasSecretAfterSave).toBe(true);
+  });
+
+  it('clears the stored secret when explicitly requested', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: true,
+      valueInput: '',
+      clearSecret: true,
+    });
+
+    expect(result.value).toBe('');
+    expect(result.clearStoredSecret).toBe(true);
+    expect(result.keepsStoredSecret).toBe(false);
+    expect(result.hasSecretAfterSave).toBe(false);
+  });
+
+  it('prefers a newly entered value over a stale clear toggle', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: true,
+      valueInput: 'new-password',
+      clearSecret: true,
+    });
+
+    expect(result.value).toBe('new-password');
+    expect(result.clearStoredSecret).toBe(false);
+    expect(result.keepsStoredSecret).toBe(false);
+    expect(result.hasSecretAfterSave).toBe(true);
+  });
+
+  it('does not emit a clear flag for a brand new blank field', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: false,
+      valueInput: '',
+      clearSecret: false,
+    });
+
+    expect(result.value).toBe('');
+    expect(result.clearStoredSecret).toBe(false);
+    expect(result.keepsStoredSecret).toBe(false);
+    expect(result.hasSecretAfterSave).toBe(false);
+  });
+
+  it('supports force clearing stored secrets', () => {
+    const result = resolveConnectionSecretDraft({
+      hasSecret: true,
+      valueInput: 'temporary',
+      clearSecret: false,
+      forceClear: true,
+    });
+
+    expect(result.value).toBe('');
+    expect(result.clearStoredSecret).toBe(true);
+    expect(result.keepsStoredSecret).toBe(false);
+    expect(result.hasSecretAfterSave).toBe(false);
+  });
+});
+