fix(grokbuild): complete proxy and deep-link integrations (#5677)

* fix(grokbuild): complete proxy integration

* fix(deeplink): preview GrokBuild configs safely

* test(app): stabilize provider integration suite

* fix(grokbuild): address review feedback

* fix(grokbuild): resolve remaining review findings

* fix(grokbuild): use native sessions and harden previews

tests/components/ProxyTabContent.apps.test.ts

@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest";
+import { FAILOVER_APPS } from "@/components/settings/ProxyTabContent";
+
+describe("ProxyTabContent failover apps", () => {
+  it("exposes Grok Build alongside the existing failover applications", () => {
+    expect(FAILOVER_APPS.map(({ id }) => id)).toEqual([
+      "claude",
+      "codex",
+      "gemini",
+      "grokbuild",
+    ]);
+  });
+});