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

electron/preload.ts

@@ -53,4 +53,5 @@ contextBridge.exposeInMainWorld('electronAPI', {
   terminalStop: () => ipcRenderer.invoke('terminal-stop'),
   terminalGetStatus: () => ipcRenderer.invoke('terminal-get-status'),
   terminalGetPort: () => ipcRenderer.invoke('terminal-get-port'),
+  createWindow: (tabData: { route: string; title: string }) => ipcRenderer.invoke('create-window', tabData),
 })