refactor: 统一端口配置，通过 IPC 获取而非硬编码

src/types/electron.d.ts

@@ -43,6 +43,7 @@ export interface ElectronAPI {
   xcOpenCodeWebStart: () => Promise<{ success: boolean; error?: string }>
   xcOpenCodeWebStop: () => Promise<{ success: boolean; error?: string }>
   xcOpenCodeWebGetStatus: () => Promise<{ running: boolean; port: number }>
+  xcOpenCodeWebGetPort: () => Promise<{ port: number }>
 }
 
 declare global {