feat(plugin-import-export): adds sort order control and sync with sort-by field (#13478)

### What?

This PR adds a dedicated `sortOrder` select field (Ascending /
Descending) to the import-export plugin, alongside updates to the
existing `SortBy` component. The new field and component logic keep the
sort field (`sort`) in sync with the selected sort direction.

### Why?

Previously, descending sorting did not work. While the `SortBy` field
could read the list view’s `query.sort` param, if the value contained a
leading dash (e.g. `-title`), it would not be handled correctly. Only
ascending sorts such as `sort=title` worked, and the preview table would
not reflect a descending order.

### How?

- Added a new `sortOrder` select field to the export options schema.
- Implemented a `SortOrder` custom component using ReactSelect:
- On new exports, reads `query.sort` from the list view and sets both
`sortOrder` and `sort` (combined value with or without a leading dash).
  - Handles external changes to `sort` that include a leading dash.
- Updated `SortBy`:
- No longer writes to `sort` during initial hydration—`SortOrder` owns
initial value setting.
- On user field changes, writes the combined value using the current
`sortOrder`.

test/plugin-import-export/int.spec.ts

@@ -227,6 +227,60 @@ describe('@payloadcms/plugin-import-export', () => {
       ).rejects.toThrow(/Limit/)
     })
 
+    it('should export results sorted ASC by title when sort="title"', async () => {
+      let doc = await payload.create({
+        collection: 'exports',
+        user,
+        data: {
+          collectionSlug: 'pages',
+          format: 'csv',
+          sort: 'title',
+          where: {
+            or: [{ title: { contains: 'Title' } }, { title: { contains: 'Array' } }],
+          },
+        },
+      })
+
+      doc = await payload.findByID({
+        collection: 'exports',
+        id: doc.id,
+      })
+
+      expect(doc.filename).toBeDefined()
+      const expectedPath = path.join(dirname, './uploads', doc.filename as string)
+      const data = await readCSV(expectedPath)
+
+      expect(data[0].id).toBeDefined()
+      expect(data[0].title).toStrictEqual('Array 0')
+    })
+
+    it('should export results sorted DESC by title when sort="-title"', async () => {
+      let doc = await payload.create({
+        collection: 'exports',
+        user,
+        data: {
+          collectionSlug: 'pages',
+          format: 'csv',
+          sort: '-title',
+          where: {
+            or: [{ title: { contains: 'Title' } }, { title: { contains: 'Array' } }],
+          },
+        },
+      })
+
+      doc = await payload.findByID({
+        collection: 'exports',
+        id: doc.id,
+      })
+
+      expect(doc.filename).toBeDefined()
+      const expectedPath = path.join(dirname, './uploads', doc.filename as string)
+      const data = await readCSV(expectedPath)
+
+      expect(data[0].id).toBeDefined()
+      expect(data[0].title).toStrictEqual('Title 4')
+    })
+
     it('should create a file for collection csv with draft data', async () => {
       const draftPage = await payload.create({
         collection: 'pages',

test/plugin-import-export/payload-types.ts

@@ -270,6 +270,7 @@ export interface Export {
   limit?: number | null;
   page?: number | null;
   sort?: string | null;
+  sortOrder?: ('asc' | 'desc') | null;
   locale?: ('all' | 'en' | 'es' | 'de') | null;
   drafts?: ('yes' | 'no') | null;
   selectionToUse?: ('currentSelection' | 'currentFilters' | 'all') | null;
@@ -307,6 +308,7 @@ export interface ExportsTask {
   limit?: number | null;
   page?: number | null;
   sort?: string | null;
+  sortOrder?: ('asc' | 'desc') | null;
   locale?: ('all' | 'en' | 'es' | 'de') | null;
   drafts?: ('yes' | 'no') | null;
   selectionToUse?: ('currentSelection' | 'currentFilters' | 'all') | null;
@@ -609,6 +611,7 @@ export interface ExportsSelect<T extends boolean = true> {
   limit?: T;
   page?: T;
   sort?: T;
+  sortOrder?: T;
   locale?: T;
   drafts?: T;
   selectionToUse?: T;
@@ -637,6 +640,7 @@ export interface ExportsTasksSelect<T extends boolean = true> {
   limit?: T;
   page?: T;
   sort?: T;
+  sortOrder?: T;
   locale?: T;
   drafts?: T;
   selectionToUse?: T;
@@ -729,6 +733,7 @@ export interface TaskCreateCollectionExport {
     limit?: number | null;
     page?: number | null;
     sort?: string | null;
+    sortOrder?: ('asc' | 'desc') | null;
     locale?: ('all' | 'en' | 'es' | 'de') | null;
     drafts?: ('yes' | 'no') | null;
     selectionToUse?: ('currentSelection' | 'currentFilters' | 'all') | null;