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/input/MultiSelect.vue

@@ -93,13 +93,12 @@
       #header
     >
       <div class="flex flex-col px-2 pt-2 pb-0">
-        <SearchBox
+        <SearchInput
           v-if="showSearchBox"
           v-model="searchQuery"
           :class="showSelectedCount || showClearButton ? 'mb-2' : ''"
-          :show-order="true"
-          :show-border="true"
-          :place-holder="searchPlaceholder"
+          :placeholder="searchPlaceholder"
+          size="sm"
         />
         <div
           v-if="showSelectedCount || showClearButton"
@@ -182,7 +181,7 @@ import MultiSelect from 'primevue/multiselect'
 import { computed, useAttrs } from 'vue'
 import { useI18n } from 'vue-i18n'
 
-import SearchBox from '@/components/common/SearchBox.vue'
+import SearchInput from '@/components/ui/search-input/SearchInput.vue'
 import Button from '@/components/ui/button/Button.vue'
 import { usePopoverSizing } from '@/composables/usePopoverSizing'
 import { cn } from '@/utils/tailwindUtil'