feat(sidebar): autofocus search input in Workflows, Model, and Node tabs (#7179)

## Summary
This PR improves the user experience by automatically focusing the
search input field when opening the Workflows, Model Library, or Node
Library sidebar tabs.

## Changes
- **SearchBox.vue**: Exposed a `focus()` method to allow parent
components to programmatically set focus on the input.
- **WorkflowsSidebarTab.vue**: Added a watcher to focus the search box
when the tab is activated.
- **ModelLibrarySidebarTab.vue**: Added autofocus on component mount.
- **NodeLibrarySidebarTab.vue**: Added autofocus on component mount.

## Motivation
Users often switch to these tabs specifically to search for an item.
Automatically focusing the search box reduces friction and saves a
click.



https://github.com/user-attachments/assets/8438e71c-a5e4-4b6c-8665-04d535d3ad8e

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7179-feat-sidebar-autofocus-search-input-in-Workflows-Model-and-Node-tabs-2c06d73d36508199b8c0e83d19f1cd84)
by [Unito](https://www.unito.io)

src/components/common/SearchBox.vue

@@ -10,6 +10,7 @@
         @click="$emit('showFilter', $event)"
       />
       <InputText
+        ref="inputRef"
         class="search-box-input w-full"
         :model-value="modelValue"
         :placeholder="placeholder"
@@ -48,6 +49,7 @@ import Button from 'primevue/button'
 import IconField from 'primevue/iconfield'
 import InputIcon from 'primevue/inputicon'
 import InputText from 'primevue/inputtext'
+import { ref } from 'vue'
 
 import type { SearchFilter } from './SearchFilterChip.vue'
 import SearchFilterChip from './SearchFilterChip.vue'
@@ -77,6 +79,14 @@ const emit = defineEmits<{
   (e: 'removeFilter', filter: TFilter): void
 }>()
 
+const inputRef = ref()
+
+defineExpose({
+  focus: () => {
+    inputRef.value?.$el?.focus()
+  }
+})
+
 const emitSearch = debounce((value: string) => {
   emit('search', value, filters)
 }, debounceTime)