[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/remoteServerPromptRenderer.js

@@ -0,0 +1,40 @@
+(function () {
+  const input = document.getElementById("url-input");
+  const errorEl = document.getElementById("error");
+  const saveBtn = document.getElementById("save-btn");
+  const cancelBtn = document.getElementById("cancel-btn");
+
+  function isValidOrEmpty(value) {
+    const trimmed = value.trim();
+    if (!trimmed) return true; // empty = disconnect, handled by main process
+    try {
+      const parsed = new URL(trimmed);
+      return parsed.protocol === "http:" || parsed.protocol === "https:";
+    } catch {
+      return false;
+    }
+  }
+
+  window.remoteServerPrompt.getInitialUrl().then((url) => {
+    input.value = url || "";
+    input.focus();
+  });
+
+  saveBtn.addEventListener("click", () => {
+    const value = input.value.trim();
+    if (!isValidOrEmpty(value)) {
+      errorEl.textContent = "Enter a valid http:// or https:// URL, or leave blank to disconnect.";
+      return;
+    }
+    window.remoteServerPrompt.submit(value);
+  });
+
+  cancelBtn.addEventListener("click", () => {
+    window.remoteServerPrompt.cancel();
+  });
+
+  input.addEventListener("keydown", (event) => {
+    if (event.key === "Enter") saveBtn.click();
+    if (event.key === "Escape") cancelBtn.click();
+  });
+})();