fix(DisplayCarousel): use back button in grid view and remove hover icons (#10655)

## Summary
- Grid view top-left icon changed from square to back arrow
(`arrow-left`) per Figma spec
- Back button is always visible in grid view (no longer
hover-dependent), uses sticky positioning
- Removed hover opacity effect on grid thumbnails

## Related
- Figma:
https://www.figma.com/design/vALUV83vIdBzEsTJAhQgXq/Comfy-Design-System?node-id=6008-83034&m=dev
- Figma:
https://www.figma.com/design/vALUV83vIdBzEsTJAhQgXq/Comfy-Design-System?node-id=6008-83069&m=dev

## Test plan
- [x] All 31 existing DisplayCarousel tests pass
- [ ] Visual check: grid view shows back arrow icon (top-left, always
visible)
- [ ] Visual check: hovering grid thumbnails shows no overlay icons
- [ ] Verify back button stays visible when scrolling through many grid
items

## Screenshot
### Before
<img width="492" height="364" alt="스크린샷 2026-03-28 오후 4 31 54"
src="https://github.com/user-attachments/assets/f9f36521-e993-45de-b692-59fba22a026d"
/>
<img width="457" height="400" alt="스크린샷 2026-03-28 오후 4 32 03"
src="https://github.com/user-attachments/assets/004f6380-8ad7-4167-b1f4-ebc4bdb559cc"
/>

### After
<img width="596" height="388" alt="스크린샷 2026-03-28 오후 4 31 43"
src="https://github.com/user-attachments/assets/e5585887-ad36-42e3-a6c0-e6eacb90dad7"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10655-fix-DisplayCarousel-use-back-button-in-grid-view-and-remove-hover-icons-3316d73d365081c5826afd63c50994ba)
by [Unito](https://www.unito.io)

src/renderer/extensions/vueNodes/widgets/components/DisplayCarousel.test.ts

@@ -341,7 +341,7 @@ describe('DisplayCarousel Grid Mode', () => {
     )
   })
 
-  it('switches back to single mode via toggle button', async () => {
+  it('grid mode has no overlay icons', async () => {
     const wrapper = createGalleriaWrapper([...TEST_IMAGES_SMALL])
 
     // Switch to grid via focus on image container
@@ -350,19 +350,69 @@ describe('DisplayCarousel Grid Mode', () => {
     await wrapper.find('[aria-label="Switch to grid view"]').trigger('click')
     await nextTick()
 
-    // Focus the grid container to reveal toggle
+    // Grid mode should have no toggle/back button
+    expect(wrapper.find('[aria-label="Switch to single view"]').exists()).toBe(
+      false
+    )
+    expect(wrapper.find('[aria-label="Switch to grid view"]').exists()).toBe(
+      false
+    )
+  })
+
+  it('always uses undo-2 icon for grid toggle button', async () => {
+    const wrapper = createGalleriaWrapper([...TEST_IMAGES_SMALL])
+
+    // Show controls
     await findImageContainer(wrapper).trigger('focusin')
     await nextTick()
 
-    // Switch back to single
-    const singleToggle = wrapper.find('[aria-label="Switch to single view"]')
-    expect(singleToggle.exists()).toBe(true)
+    const toggleBtn = wrapper.find('[aria-label="Switch to grid view"]')
+    expect(toggleBtn.find('i').classes()).toContain('icon-[lucide--undo-2]')
 
-    await singleToggle.trigger('click')
+    // Switch to grid and back
+    await toggleBtn.trigger('click')
     await nextTick()
 
-    // Should be back in single mode with main image
-    expect(wrapper.find('[aria-label="Previous image"]').exists()).toBe(true)
+    const gridButtons = wrapper
+      .findAll('button')
+      .filter((btn) => btn.find('img').exists())
+    await gridButtons[0].trigger('click')
+    await nextTick()
+
+    await findImageContainer(wrapper).trigger('focusin')
+    await nextTick()
+
+    // Icon should still be undo-2
+    const toggleBtnAfter = wrapper.find('[aria-label="Switch to grid view"]')
+    expect(toggleBtnAfter.find('i').classes()).toContain(
+      'icon-[lucide--undo-2]'
+    )
+  })
+
+  it('shows grid button in single mode after selecting from grid', async () => {
+    const wrapper = createGalleriaWrapper([...TEST_IMAGES_SMALL])
+
+    // Switch to grid
+    await findImageContainer(wrapper).trigger('focusin')
+    await nextTick()
+    await wrapper.find('[aria-label="Switch to grid view"]').trigger('click')
+    await nextTick()
+
+    // Click first grid image to go back to single mode
+    const gridButtons = wrapper
+      .findAll('button')
+      .filter((btn) => btn.find('img').exists())
+    await gridButtons[0].trigger('click')
+    await nextTick()
+
+    // Hover to reveal controls
+    await findImageContainer(wrapper).trigger('focusin')
+    await nextTick()
+
+    // Should still show grid view button (same icon always)
+    expect(wrapper.find('[aria-label="Switch to grid view"]').exists()).toBe(
+      true
+    )
   })
 
   it('clicking grid image switches to single mode focused on that image', async () => {
@@ -404,8 +454,8 @@ describe('DisplayCarousel Grid Mode', () => {
     await wrapper.setProps({ modelValue: [TEST_IMAGES_SMALL[0]] })
     await nextTick()
 
-    // Should revert to single mode (no grid toggle visible)
-    expect(wrapper.find('[aria-label="Switch to single view"]').exists()).toBe(
+    // Should revert to single mode (single image, no grid button)
+    expect(wrapper.find('[aria-label="Switch to grid view"]').exists()).toBe(
       false
     )
   })

src/renderer/extensions/vueNodes/widgets/components/DisplayCarousel.vue

@@ -36,7 +36,7 @@
             :aria-label="t('g.switchToGridView')"
             @click="switchToGrid"
           >
-            <i class="icon-[lucide--layout-grid] size-4" />
+            <i class="icon-[lucide--undo-2] size-4" />
           </button>
 
           <!-- Action Buttons (hover, top-right) -->
@@ -142,41 +142,19 @@
           ref="gridContainerEl"
           class="relative h-72 overflow-x-hidden overflow-y-auto rounded-sm bg-component-node-background"
           tabindex="0"
-          @mouseenter="isHovered = true"
-          @mouseleave="isHovered = false"
-          @focusin="isFocused = true"
-          @focusout="handleFocusOut"
         >
-          <!-- Toggle to Single (hover, top-left) -->
-          <button
-            v-if="showControls"
-            :class="toggleButtonClass"
-            class="absolute top-2 left-2 z-10"
-            :aria-label="t('g.switchToSingleView')"
-            @click="switchToSingle"
-          >
-            <i class="icon-[lucide--square] size-4" />
-          </button>
-
           <div class="flex flex-wrap content-start gap-1">
             <button
               v-for="(item, index) in galleryImages"
               :key="getItemSrc(item)"
               class="size-14 shrink-0 cursor-pointer overflow-hidden border-0 p-0"
               :aria-label="getItemAlt(item, index)"
-              @mouseenter="hoveredGridIndex = index"
-              @mouseleave="hoveredGridIndex = -1"
               @click="selectFromGrid(index)"
             >
               <img
                 :src="getItemThumbnail(item)"
                 :alt="getItemAlt(item, index)"
-                :class="
-                  cn(
-                    'size-full object-cover transition-opacity',
-                    hoveredGridIndex === index && 'opacity-50'
-                  )
-                "
+                class="size-full object-cover"
               />
             </button>
           </div>
@@ -229,7 +207,6 @@ const activeIndex = ref(0)
 const displayMode = ref<DisplayMode>('single')
 const isHovered = ref(false)
 const isFocused = ref(false)
-const hoveredGridIndex = ref(-1)
 const imageDimensions = ref<string | null>(null)
 const thumbnailRefs = ref<(HTMLElement | null)[]>([])
 const imageContainerEl = ref<HTMLDivElement>()
@@ -359,11 +336,6 @@ function switchToGrid() {
   displayMode.value = 'grid'
 }
 
-function switchToSingle() {
-  isHovered.value = false
-  displayMode.value = 'single'
-}
-
 function selectFromGrid(index: number) {
   activeIndex.value = index
   imageDimensions.value = null