✨ feat(connection-modal): 新增SSH私钥文件浏览选择能力

- 新增私钥文件选择入口，减少手动输入路径错误
- 复用系统文件对话框并自动回填私钥路径
- 保留手动输入作为兜底方式
- refs #119

frontend/wailsjs/go/app/App.d.ts

@@ -156,6 +156,8 @@ export function SelectDriverDownloadDirectory(arg1:string):Promise<connection.Qu
 
 export function SelectDriverPackageFile(arg1:string):Promise<connection.QueryResult>;
 
+export function SelectSSHKeyFile(arg1:string):Promise<connection.QueryResult>;
+
 export function SetWindowTranslucency(arg1:number,arg2:number):Promise<void>;
 
 export function TestConnection(arg1:connection.ConnectionConfig):Promise<connection.QueryResult>;

frontend/wailsjs/go/app/App.js

@@ -306,6 +306,10 @@ export function SelectDriverPackageFile(arg1) {
   return window['go']['app']['App']['SelectDriverPackageFile'](arg1);
 }
 
+export function SelectSSHKeyFile(arg1) {
+  return window['go']['app']['App']['SelectSSHKeyFile'](arg1);
+}
+
 export function SetWindowTranslucency(arg1, arg2) {
   return window['go']['app']['App']['SetWindowTranslucency'](arg1, arg2);
 }