feat(UI): Support custcom css in mini window (#4255)

* feat(UI): enable custom CSS functionality with miniWindow

* feat(UI): implement custom CSS handling in IPC and update related components

src/preload/index.d.ts

@@ -29,6 +29,7 @@ declare global {
       setTrayOnClose: (isActive: boolean) => void
       restartTray: () => void
       setTheme: (theme: 'light' | 'dark') => void
+      setCustomCss: (css: string) => void
       reload: () => void
       clearCache: () => Promise<{ success: boolean; error?: string }>
       system: {

src/preload/index.ts

@@ -19,6 +19,7 @@ const api = {
   setTrayOnClose: (isActive: boolean) => ipcRenderer.invoke(IpcChannel.App_SetTrayOnClose, isActive),
   restartTray: () => ipcRenderer.invoke(IpcChannel.App_RestartTray),
   setTheme: (theme: 'light' | 'dark') => ipcRenderer.invoke(IpcChannel.App_SetTheme, theme),
+  setCustomCss: (css: string) => ipcRenderer.invoke(IpcChannel.App_SetCustomCss, css),
   openWebsite: (url: string) => ipcRenderer.invoke(IpcChannel.Open_Website, url),
   clearCache: () => ipcRenderer.invoke(IpcChannel.App_ClearCache),
   system: {