FIX - keep CityWarn rendering crisp

Disable the persistent compositor hint for the CityWarn app window so text does not alternate between blurred and sharp states during interaction. Keep the exception scoped to CityWarn and cover the host-class contract.

frontend/src/assets/main.css

@@ -845,7 +845,9 @@ button {
 }
 .phone-dynamic-island-enter-active,
 .phone-dynamic-island-leave-active {
-  transition: opacity 180ms ease, transform 220ms cubic-bezier(0.22, 1, 0.36, 1);
+  transition:
+    opacity 180ms ease,
+    transform 220ms cubic-bezier(0.22, 1, 0.36, 1);
 }
 .phone-dynamic-island-enter-from,
 .phone-dynamic-island-leave-to {
@@ -3544,6 +3546,11 @@ button {
   backface-visibility: hidden;
   will-change: transform, border-radius, opacity;
 }
+.app-window--citywarn {
+  backface-visibility: visible;
+  filter: none;
+  will-change: auto;
+}
 .app-window-enter-active {
   transition:
     transform 0.46s cubic-bezier(0.32, 0.72, 0, 1),

frontend/src/views/PhoneAppWindow.contract.test.ts

@@ -15,5 +15,6 @@ describe('PhoneAppWindow bundle contract', () => {
     expect(source).toContain("app.value?.id === 'app-store'")
     expect(source).toContain('? AppStoreApp : app.value?.component')
     expect(source).toContain('<component :is="builtinAppComponent" />')
+    expect(source).toContain("'app-window--citywarn': app.id === 'citywarn'")
   })
 })

frontend/src/views/PhoneAppWindow.vue

@@ -27,7 +27,12 @@ const launchStyle = computed(() => {
 </script>
 
 <template>
-  <div v-if="app" class="app-window" :style="launchStyle">
+  <div
+    v-if="app"
+    class="app-window"
+    :class="{ 'app-window--citywarn': app.id === 'citywarn' }"
+    :style="launchStyle"
+  >
     <CustomAppFrame
       v-if="isExternalPhoneApp(app)"
       :key="getCustomAppFrameKey(app)"