feat(onboarding): wire plugin-backed auth choices

src/commands/auth-choice.apply.google-antigravity.ts

@@ -0,0 +1,14 @@
+import type { ApplyAuthChoiceParams, ApplyAuthChoiceResult } from "./auth-choice.apply.js";
+import { applyAuthChoicePluginProvider } from "./auth-choice.apply.plugin-provider.js";
+
+export async function applyAuthChoiceGoogleAntigravity(
+  params: ApplyAuthChoiceParams,
+): Promise<ApplyAuthChoiceResult | null> {
+  return await applyAuthChoicePluginProvider(params, {
+    authChoice: "google-antigravity",
+    pluginId: "google-antigravity-auth",
+    providerId: "google-antigravity",
+    methodId: "oauth",
+    label: "Google Antigravity",
+  });
+}