feat: unify search components by replacing SearchBox/SearchBoxV2 with SearchInput (#9644)

## Summary

Replace legacy `SearchBox` (PrimeVue) and `SearchBoxV2` with the unified
`SearchInput` (reka-ui) component across all consumers.

## Changes

- **What**: Remove `SearchBox.vue`, `SearchBoxV2.vue`, their tests and
stories. Migrate all 14 consumers to `SearchInput`. Move layout classes
to `ComboboxRoot` for proper flex sizing. Extract filter button/chips in
`NodeLibrarySidebarTab`. Standardize modal search width to `flex-1
max-w-lg`.
- **Dependencies**: None new — `SearchInput` already existed using
reka-ui

## Review Focus

- `NodeLibrarySidebarTab.vue`: filter button and `SearchFilterChip`
rendering moved outside the search component
- `SearchInput.vue`: `className` now applied to `ComboboxRoot` instead
of `ComboboxAnchor` for correct flex layout
- Modal dialogs (`WorkflowTemplateSelectorDialog`, `AssetBrowserModal`,
`SampleModelSelector`) unified to `flex-1 max-w-lg`

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9644-feat-unify-search-components-by-replacing-SearchBox-SearchBoxV2-with-SearchInput-31e6d73d365081ebac55cb265f33b631)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: github-actions <github-actions@github.com>

src/components/sidebar/tabs/NodeLibrarySidebarTabV2.vue

@@ -3,7 +3,7 @@
     <template #header>
       <TabsRoot v-model="selectedTab" class="flex flex-col">
         <div class="flex items-center justify-between gap-2 px-2 pb-2 2xl:px-4">
-          <SearchBox
+          <SearchInput
             ref="searchBoxRef"
             v-model="searchQuery"
             :placeholder="$t('g.search') + '...'"
@@ -180,7 +180,7 @@ import { computed, nextTick, onMounted, ref, watchEffect } from 'vue'
 import { useI18n } from 'vue-i18n'
 
 import { resolveEssentialsDisplayName } from '@/constants/essentialsDisplayNames'
-import SearchBox from '@/components/common/SearchBoxV2.vue'
+import SearchInput from '@/components/ui/search-input/SearchInput.vue'
 import { useFeatureFlags } from '@/composables/useFeatureFlags'
 import { useNodeDragToCanvas } from '@/composables/node/useNodeDragToCanvas'
 import { usePerTabState } from '@/composables/usePerTabState'
@@ -253,7 +253,7 @@ const filterOptions = ref<Record<NodeCategoryId, boolean>>({
 
 const { t } = useI18n()
 
-const searchBoxRef = ref<InstanceType<typeof SearchBox> | null>(null)
+const searchBoxRef = ref<InstanceType<typeof SearchInput> | null>(null)
 const searchQuery = ref('')
 const expandedKeysByTab = ref<Record<TabId, string[]>>({
   essentials: [],