feat: add DropZone Storybook coverage for file upload states (#9690)

## Summary
- align the linear-mode `DropZone` upload indicator with the Figma file
upload states
- add a co-located Storybook story for the default and hover variants
- add a `forceHovered` preview prop so Storybook can render the hover
state deterministically

## Validation
- `pnpm typecheck` (run in the original workspace with dependencies
installed)
- `pnpm lint` (passes with one pre-existing warning in
`src/lib/litegraph/src/ContextMenu.ts`)
- Storybook smoke check is currently blocked by an existing workspace
issue: `vite-plugin-inspect` fails with `Can not found environment
context for client`

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9690-feat-add-DropZone-Storybook-coverage-for-file-upload-states-31f6d73d365081ae9eabdde6b5915f26)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>

src/renderer/extensions/linearMode/DropZone.stories.ts

@@ -0,0 +1,131 @@
+import type {
+  ComponentPropsAndSlots,
+  Meta,
+  StoryObj
+} from '@storybook/vue3-vite'
+import { ref } from 'vue'
+
+import DropZone from './DropZone.vue'
+
+type StoryArgs = ComponentPropsAndSlots<typeof DropZone>
+
+const defaultLabel = 'Click to browse or drag an image'
+const defaultIconClass = 'icon-[lucide--image]'
+
+function createFileInput(onFile: (file: File) => void) {
+  const input = document.createElement('input')
+  input.type = 'file'
+  input.accept = 'image/*'
+  input.addEventListener('change', () => {
+    const file = input.files?.[0]
+    if (file) onFile(file)
+  })
+  return input
+}
+
+function fileToObjectUrl(file: File): string {
+  return URL.createObjectURL(file)
+}
+
+function extractDroppedImageFile(e: DragEvent): File | undefined {
+  return Array.from(e.dataTransfer?.files ?? []).find((f) =>
+    f.type.startsWith('image/')
+  )
+}
+
+const renderStory = (args: StoryArgs) => ({
+  components: { DropZone },
+  setup() {
+    const imageUrl = ref<string | undefined>(undefined)
+    const hovered = ref(false)
+
+    function handleFile(file: File) {
+      imageUrl.value = fileToObjectUrl(file)
+    }
+
+    const onDragOver = (e: DragEvent) => {
+      if (!e.dataTransfer?.items) return false
+      return Array.from(e.dataTransfer.items).some(
+        (item) => item.kind === 'file' && item.type.startsWith('image/')
+      )
+    }
+
+    const onDragDrop = (e: DragEvent) => {
+      const file = extractDroppedImageFile(e)
+      if (file) handleFile(file)
+      return !!file
+    }
+
+    const onClick = () => {
+      createFileInput(handleFile).click()
+    }
+
+    const dropIndicator = ref({
+      ...args.dropIndicator,
+      onClick
+    })
+
+    return { args, onDragOver, onDragDrop, dropIndicator, imageUrl, hovered }
+  },
+  template: `
+    <div
+      @mouseenter="hovered = true"
+      @mouseleave="hovered = false"
+    >
+      <DropZone
+        v-bind="args"
+        :on-drag-over="onDragOver"
+        :on-drag-drop="onDragDrop"
+        :force-hovered="hovered"
+        :drop-indicator="{
+          ...dropIndicator,
+          imageUrl: imageUrl ?? dropIndicator.imageUrl
+        }"
+      />
+    </div>
+  `
+})
+
+const meta: Meta<StoryArgs> = {
+  title: 'Components/FileUpload',
+  component: DropZone,
+  tags: ['autodocs'],
+  parameters: {
+    layout: 'centered',
+    docs: {
+      description: {
+        component:
+          'Linear mode drag-and-drop target with a file upload indicator. Click to browse or drag an image file to upload.'
+      }
+    }
+  },
+  argTypes: {
+    onDragOver: { table: { disable: true } },
+    onDragDrop: { table: { disable: true } },
+    dropIndicator: { control: false },
+    forceHovered: { table: { disable: true } }
+  },
+  args: {
+    dropIndicator: {
+      label: defaultLabel,
+      iconClass: defaultIconClass
+    }
+  },
+  decorators: [
+    (story) => ({
+      components: { story },
+      template: `
+        <div class="w-[440px] rounded-xl bg-component-node-background p-4">
+          <story />
+        </div>
+      `
+    })
+  ]
+}
+
+export default meta
+type Story = StoryObj<typeof meta>
+
+export const Default: Story = {
+  render: renderStory
+}

src/renderer/extensions/linearMode/DropZone.vue

@@ -1,10 +1,15 @@
 <script setup lang="ts">
 import { useDropZone } from '@vueuse/core'
-import { ref } from 'vue'
+import { computed, ref } from 'vue'
 
 import { cn } from '@/utils/tailwindUtil'
 
-const props = defineProps<{
+const {
+  onDragOver,
+  onDragDrop,
+  dropIndicator,
+  forceHovered = false
+} = defineProps<{
   onDragOver?: (e: DragEvent) => boolean
   onDragDrop?: (e: DragEvent) => Promise<boolean> | boolean
   dropIndicator?: {
@@ -13,6 +18,7 @@ const props = defineProps<{
     label?: string
     onClick?: (e: MouseEvent) => void
   }
+  forceHovered?: boolean
 }>()
 
 const dropZoneRef = ref<HTMLElement | null>(null)
@@ -23,53 +29,83 @@ const { isOverDropZone } = useDropZone(dropZoneRef, {
     // Stop propagation to prevent global handlers from creating a new node
     event?.stopPropagation()
 
-    if (props.onDragDrop && event) {
-      props.onDragDrop(event)
+    if (onDragDrop && event) {
+      onDragDrop(event)
     }
     canAcceptDrop.value = false
   },
   onOver: (_, event) => {
-    if (props.onDragOver && event) {
-      canAcceptDrop.value = props.onDragOver(event)
+    if (onDragOver && event) {
+      canAcceptDrop.value = onDragOver(event)
     }
   },
   onLeave: () => {
     canAcceptDrop.value = false
   }
 })
+
+const isHovered = computed(
+  () => forceHovered || (canAcceptDrop.value && isOverDropZone.value)
+)
+const indicatorTag = computed(() => (dropIndicator?.onClick ? 'button' : 'div'))
 </script>
 <template>
   <div
     v-if="onDragOver && onDragDrop"
     ref="dropZoneRef"
+    data-slot="drop-zone"
     :class="
       cn(
-        'rounded-lg ring-primary-500 ring-inset',
-        canAcceptDrop && isOverDropZone && 'bg-primary-500/10 ring-4'
+        'rounded-lg transition-colors',
+        isHovered && 'bg-component-node-widget-background-hovered'
       )
     "
   >
     <slot />
-    <div
+    <component
+      :is="indicatorTag"
       v-if="dropIndicator"
+      :type="dropIndicator?.onClick ? 'button' : undefined"
+      :aria-label="dropIndicator?.onClick ? dropIndicator.label : undefined"
+      data-slot="drop-zone-indicator"
       :class="
         cn(
-          'm-3 flex h-25 flex-col items-center justify-center gap-2 rounded-lg border border-dashed border-border-subtle py-2',
+          'm-3 block w-[calc(100%-1.5rem)] appearance-none overflow-hidden rounded-lg border border-node-component-border bg-transparent p-1 text-left text-component-node-foreground-secondary transition-colors',
           dropIndicator?.onClick && 'cursor-pointer'
         )
       "
       @click.prevent="dropIndicator?.onClick?.($event)"
     >
-      <img
-        v-if="dropIndicator?.imageUrl"
-        class="h-23"
-        :src="dropIndicator?.imageUrl"
-      />
-      <template v-else>
-        <span v-if="dropIndicator.label" v-text="dropIndicator.label" />
-        <i v-if="dropIndicator.iconClass" :class="dropIndicator.iconClass" />
-      </template>
-    </div>
+      <div
+        :class="
+          cn(
+            'flex min-h-23 w-full flex-col items-center justify-center gap-2 rounded-[7px] p-6 text-center text-sm/tight transition-colors',
+            isHovered &&
+              !dropIndicator?.imageUrl &&
+              'border border-dashed border-component-node-foreground-secondary bg-component-node-widget-background-hovered'
+          )
+        "
+      >
+        <img
+          v-if="dropIndicator?.imageUrl"
+          class="max-h-23 rounded-md object-contain"
+          :alt="dropIndicator?.label ?? ''"
+          :src="dropIndicator?.imageUrl"
+        />
+        <template v-else>
+          <span v-if="dropIndicator.label" v-text="dropIndicator.label" />
+          <i
+            v-if="dropIndicator.iconClass"
+            :class="
+              cn(
+                'size-4 text-component-node-foreground-secondary',
+                dropIndicator.iconClass
+              )
+            "
+          />
+        </template>
+      </div>
+    </component>
   </div>
   <slot v-else />
 </template>