fix: close phase 2 journey blockers

tests/unit/adaptive-quality.test.ts

@@ -7,6 +7,7 @@ import {
   type AdaptiveQualityController,
   type QualityDecision,
 } from '@/journey/adaptive-quality';
+import type { QualityTier } from '@/journey/motion-policy';
 
 afterEach(() => {
   vi.restoreAllMocks();
@@ -265,6 +266,26 @@ describe('useAdaptiveQuality', () => {
     expect(wrapper.vm.snapshot.epoch).toBeNull();
     expect(documentRemove).toHaveBeenCalledWith('visibilitychange', expect.any(Function), { passive: true });
   });
+
+  it('never lets a visitor request bypass the device-resolved maximum', async () => {
+    const { useAdaptiveQuality } = await import('@/composables/useAdaptiveQuality');
+    Object.defineProperty(document, 'visibilityState', {
+      configurable: true,
+      value: 'visible',
+    });
+    const maximum = ref<QualityTier>('low');
+    const sceneState = ref('running');
+    const pageLifecycle = ref<'active'>('active');
+    const wrapper = mount(defineComponent({
+      setup: () => useAdaptiveQuality({ maximum, sceneState, pageLifecycle, now: () => 0 }),
+      template: '<output />',
+    }));
+
+    expect(wrapper.vm.setMaximum('high', 'manual')).toBeNull();
+    expect(wrapper.vm.snapshot).toMatchObject({ maximum: 'low', actual: 'low' });
+
+    wrapper.unmount();
+  });
 });
 
 function feedWindow(