feat: add Storybook stories for Slider components (#9634)

## Summary
- Add Storybook stories for `Slider` component matching Figma design
system variants 1:1
- Stories at `Components/Slider`: **Default** and **Disabled**
- Add hover background
(`hover:bg-component-node-widget-background-hovered`) to
`WidgetInputNumberSlider` only

## Figma reference
[Comfy Design System —
Slider](https://www.figma.com/design/vALUV83vIdBzEsTJAhQgXq/Comfy-Design-System?node-id=2-9718&m=dev)

## Scope decisions
- **Hover**: Added to `WidgetInputNumberSlider.vue` only — other widgets
need separate verification before applying
- **Invalid**: Not implemented in `Slider.vue` — excluded until
component supports it

## Files changed
- `src/components/ui/slider/Slider.stories.ts` — new
-
`src/renderer/extensions/vueNodes/widgets/components/WidgetInputNumberSlider.vue`
— add hover background

## Test plan
- [ ] `pnpm storybook` — verify Default and Disabled render under
`Components/Slider`
- [ ] Hover background visible on slider widget in app (e.g. KSampler
`cfg` slider)
- [ ] Other widget inputs (text, textarea, select) unchanged
- [ ] `pnpm typecheck` — passes
- [ ] `pnpm lint` — passes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/components/ui/slider/Slider.stories.ts

@@ -0,0 +1,77 @@
+import type {
+  ComponentPropsAndSlots,
+  Meta,
+  StoryObj
+} from '@storybook/vue3-vite'
+import { computed, ref, toRefs } from 'vue'
+
+import Slider from './Slider.vue'
+
+interface StoryArgs extends ComponentPropsAndSlots<typeof Slider> {
+  disabled: boolean
+}
+
+const meta: Meta<StoryArgs> = {
+  title: 'Components/Slider',
+  component: Slider,
+  tags: ['autodocs'],
+  parameters: { layout: 'centered' },
+  argTypes: {
+    min: { control: 'number' },
+    max: { control: 'number' },
+    step: { control: 'number' },
+    disabled: { control: 'boolean' }
+  },
+  args: {
+    min: 0,
+    max: 100,
+    step: 1,
+    disabled: false
+  },
+  decorators: [
+    (story) => ({
+      components: { story },
+      template: '<div class="w-72"><story /></div>'
+    })
+  ]
+}
+
+export default meta
+type Story = StoryObj<typeof meta>
+
+export const Default: Story = {
+  render: (args) => ({
+    components: { Slider },
+    setup() {
+      const { min, max, step, disabled } = toRefs(args)
+      const value = ref([36])
+      const display = computed(() => value.value[0])
+      return { value, display, min, max, step, disabled }
+    },
+    template: `
+      <div class="flex items-center gap-4 rounded-lg bg-component-node-widget-background px-3 py-2">
+        <Slider v-model="value" :min :max :step :disabled class="flex-1" />
+        <span class="w-14 shrink-0 text-right text-xs text-component-node-foreground">{{ display }}</span>
+      </div>
+    `
+  })
+}
+
+export const Disabled: Story = {
+  args: { disabled: true },
+  render: (args) => ({
+    components: { Slider },
+    setup() {
+      const { min, max, step, disabled } = toRefs(args)
+      const value = ref([36])
+      const display = computed(() => value.value[0])
+      return { value, display, min, max, step, disabled }
+    },
+    template: `
+      <div class="flex items-center gap-4 rounded-lg bg-component-node-widget-background px-3 py-2">
+        <Slider v-model="value" :min :max :step :disabled class="flex-1" />
+        <span class="w-14 shrink-0 text-right text-xs text-component-node-foreground">{{ display }}</span>
+      </div>
+    `
+  })
+}

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

@@ -1,6 +1,13 @@
 <template>
   <WidgetLayoutField :widget="widget">
-    <div :class="cn(WidgetInputBaseClass, 'flex items-center gap-2 pr-2 pl-3')">
+    <div
+      :class="
+        cn(
+          WidgetInputBaseClass,
+          'flex items-center gap-2 pr-2 pl-3 not-disabled:hover:bg-component-node-widget-background-hovered'
+        )
+      "
+    >
       <Slider
         :model-value="[modelValue]"
         v-bind="filteredProps"