🐛 fix(connection-modal): 支持编辑态回填已保存密码并保持默认遮罩

- 编辑连接前主动拉取可编辑配置，恢复主密码与 SSH 等已保存密钥
- 支持 AI 供应商编辑态回填 API Key，并保持默认遮罩展示
- 修正 AI 设置长错误提示换行展示，避免测试连接报错被裁切

Refs #489

frontend/src/utils/aiProviderEditorState.ts

@@ -8,12 +8,10 @@ export interface ProviderEditorSession {
   editingProvider: ProviderEditorConfig | null;
   formValues: Record<string, unknown> | null;
   isEditing: boolean;
-  clearProviderSecret: boolean;
   testStatus: ProviderEditorStatus;
 }
 
 interface BuildAddProviderEditorSessionInput {
-  previousClearProviderSecret?: boolean;
   presetKey?: string;
   presetBackendType: AIProviderType;
   presetBaseUrl: string;
@@ -23,15 +21,10 @@ interface BuildAddProviderEditorSessionInput {
 }
 
 interface BuildEditProviderEditorSessionInput {
-  previousClearProviderSecret?: boolean;
   provider: ProviderEditorConfig;
   formValues?: Record<string, unknown>;
 }
 
-interface BuildClosedProviderEditorSessionInput {
-  previousClearProviderSecret?: boolean;
-}
-
 export const buildAddProviderEditorSession = ({
   presetKey = 'openai',
   presetBackendType,
@@ -61,7 +54,6 @@ export const buildAddProviderEditorSession = ({
       apiFormat,
     },
     isEditing: true,
-    clearProviderSecret: false,
     testStatus: 'idle',
   };
 };
@@ -78,15 +70,13 @@ export const buildEditProviderEditorSession = ({
     apiFormat: provider.apiFormat || 'openai',
   },
   isEditing: true,
-  clearProviderSecret: false,
   testStatus: 'idle',
 });
 
-export const buildClosedProviderEditorSession = (_input?: BuildClosedProviderEditorSessionInput): ProviderEditorSession => ({
+export const buildClosedProviderEditorSession = (): ProviderEditorSession => ({
   editingProvider: null,
   formValues: null,
   isEditing: false,
-  clearProviderSecret: false,
   testStatus: 'idle',
 });