[v3.8.50] feat(electron): add Remote Server Mode to attach to an external OmniRoute instance (#8799)

Validated in local merge-train T7 (ungrouped batch 2)

electron/remoteServerPromptPreload.js

@@ -0,0 +1,15 @@
+/**
+ * Preload for the small "Connect to Remote Server" prompt window.
+ *
+ * Kept separate from the main preload.js — this window only ever loads our
+ * own bundled remoteServerPrompt.html (never remote/untrusted content), but we
+ * still keep contextIsolation on and expose the minimum surface needed.
+ */
+
+const { contextBridge, ipcRenderer } = require("electron");
+
+contextBridge.exposeInMainWorld("remoteServerPrompt", {
+  getInitialUrl: () => ipcRenderer.invoke("remote-server-prompt:get-initial-url"),
+  submit: (url) => ipcRenderer.send("remote-server-prompt:submit", url),
+  cancel: () => ipcRenderer.send("remote-server-prompt:cancel"),
+});