Added onboarding + a lightweight install banner to both the mobile login screen and the settings screen, with Android/Chromium

install prompt support and iOS “Share → Add to Home Screen” guidance. Also added a small helper + tests to decide
  when/which banner variant should show, and shared copy in common.json.

resources/js/admin/mobile/lib/mobileTour.test.ts

@@ -0,0 +1,12 @@
+import { describe, expect, it } from 'vitest';
+import { resolveTourStepKeys } from './mobileTour';
+
+describe('resolveTourStepKeys', () => {
+  it('includes the event step when there are no events', () => {
+    expect(resolveTourStepKeys(false)).toEqual(['event', 'qr', 'photos', 'push']);
+  });
+
+  it('omits the event step when events exist', () => {
+    expect(resolveTourStepKeys(true)).toEqual(['qr', 'photos', 'push']);
+  });
+});