FIX - stabilize homescreen dragging across scaling (#18)

* FIX - stabilize homescreen dragging across scaling

Render the home drag preview in an unzoomed viewport portal and normalize FiveM CEF DOM geometry before hit testing and drop settling. Cover Chrome 103, fractional scaling, 4K, ultrawide, and non-16:9 viewport behavior.

* FIX - Implement LB guest app layout and lifecycle bridge

Ensure custom LB apps are properly sized and visible by applying the required CSS contract on initialization and upon receiving the 'componentsLoaded' signal.

* FIX - match uppercase script tags in LB bridge test

frontend/src/components/AppIcon.vue

@@ -30,11 +30,13 @@ const props = withDefaults(
     app: PhoneAppDefinition
     compact?: boolean
     editMode?: boolean
+    externalDragVisual?: boolean
     showLabel?: boolean
   }>(),
   {
     compact: false,
     editMode: false,
+    externalDragVisual: false,
     showLabel: true,
   },
 )
@@ -63,14 +65,14 @@ let dragStartPage = 0
 let dragPageWidth = 0
 let dragPageMetrics: SpringboardDragMetrics | null = null
 const dragStyle = computed(() =>
-  isDragging.value
+  isDragging.value && !props.externalDragVisual
     ? {
         transform: `translate3d(${springboardPageDragCompensation(dragStartPage, phone.currentPage, dragPageWidth)}px, 0, 0)`,
       }
     : undefined,
 )
 const dragPointerStyle = computed(() =>
-  isDragging.value
+  isDragging.value && !props.externalDragVisual
     ? {
         transform: `translate3d(${dragOffset.value.x}px, ${dragOffset.value.y}px, 0)`,
       }
@@ -300,6 +302,7 @@ onBeforeUnmount(() => {
     class="app-icon-item"
     :class="{
       'app-icon-item--compact': compact,
+      'app-icon-item--drag-source': isDragging && externalDragVisual,
       'app-icon-item--dragging': isDragging,
       'app-icon-item--editing': editMode,
     }"

frontend/src/components/HomeFolderIcon.vue

@@ -22,11 +22,13 @@ const props = withDefaults(
     apps: PhoneAppDefinition[]
     defaultName: string
     editMode?: boolean
+    externalDragVisual?: boolean
     folder: HomeFolder
     showLabel?: boolean
   }>(),
   {
     editMode: false,
+    externalDragVisual: false,
     showLabel: true,
   },
 )
@@ -55,14 +57,14 @@ let stopPointerSession: (() => void) | null = null
 
 const folderName = computed(() => props.folder.name || props.defaultName)
 const dragStyle = computed(() =>
-  isDragging.value
+  isDragging.value && !props.externalDragVisual
     ? {
         transform: `translate3d(${springboardPageDragCompensation(dragStartPage, phone.currentPage, dragPageWidth)}px, 0, 0)`,
       }
     : undefined,
 )
 const dragPointerStyle = computed(() =>
-  isDragging.value
+  isDragging.value && !props.externalDragVisual
     ? {
         transform: `translate3d(${dragOffset.value.x}px, ${dragOffset.value.y}px, 0)`,
       }
@@ -232,6 +234,7 @@ onBeforeUnmount(() => {
   <div
     class="home-folder-item app-icon-item"
     :class="{
+      'app-icon-item--drag-source': isDragging && externalDragVisual,
       'app-icon-item--dragging': isDragging,
       'app-icon-item--editing': editMode,
       'home-folder-item--dragging': isDragging,