feat: add 'pop out tab as new window' functionality

- Add createWindow IPC for creating secondary windows
- Add PopoutPage for content-only rendering in new windows
- Add multi-window management to electron state
- Add '在新窗口中打开' context menu to tabs
- Fix: Use standard URL path instead of hash for React Router routing

src/types/electron.d.ts

@@ -53,6 +53,7 @@ export interface ElectronAPI {
   terminalStop: () => Promise<{ success: boolean; error?: string }>
   terminalGetStatus: () => Promise<{ running: boolean; port: number }>
   terminalGetPort: () => Promise<{ port: number }>
+  createWindow: (tabData: { route: string; title: string }) => Promise<{ success: boolean; windowId?: number; error?: string }>
 }
 
 declare global {