NestedFolderPicker: Migrate to app platform API (#106926)

* Add /children endpoint

* Update folder client

* Add comment

* Add feature toggle

* Add new version of useFoldersQuery

* Error handling

* Format

* Rename feature toggle

* Remove options and move root folder constant

* Fix feature toggle merge

* Add feature toggle again

* Rename useFoldersQuery files

* Update API spec

* Fix test

* Add test

* Better typings

---------

Co-authored-by: Clarity-89 <homes89@ukr.net>

pkg/services/featuremgmt/registry.go

@@ -1734,6 +1734,16 @@ var (
 			FrontendOnly:      true,
 			Expression:        "false", // extensions will be disabled by default
 		},
+		{
+			Name:              "foldersAppPlatformAPI",
+			Description:       "Enables use of app platform API for folders",
+			Stage:             FeatureStageExperimental,
+			Owner:             grafanaFrontendSearchNavOrganise,
+			HideFromAdminPage: true,
+			HideFromDocs:      true,
+			FrontendOnly:      true,
+			Expression:        "false",
+		},
 	}
 )
 

pkg/services/featuremgmt/toggles_gen.csv

@@ -226,3 +226,4 @@ preferLibraryPanelTitle,privatePreview,@grafana/dashboards-squad,false,false,fal
 tabularNumbers,GA,@grafana/grafana-frontend-platform,false,false,false
 newInfluxDSConfigPageDesign,privatePreview,@grafana/partner-datasources,false,false,false
 enableAppChromeExtensions,experimental,@grafana/plugins-platform-backend,false,false,true
+foldersAppPlatformAPI,experimental,@grafana/grafana-search-navigate-organise,false,false,true

pkg/services/featuremgmt/toggles_gen.go

@@ -914,4 +914,8 @@ const (
 	// FlagEnableAppChromeExtensions
 	// Set this to true to enable all app chrome extensions registered by plugins.
 	FlagEnableAppChromeExtensions = "enableAppChromeExtensions"
+
+	// FlagFoldersAppPlatformAPI
+	// Enables use of app platform API for folders
+	FlagFoldersAppPlatformAPI = "foldersAppPlatformAPI"
 )

pkg/services/featuremgmt/toggles_gen.json

@@ -1257,6 +1257,22 @@
         "hideFromDocs": true
       }
     },
+    {
+      "metadata": {
+        "name": "foldersAppPlatformAPI",
+        "resourceVersion": "1751377081192",
+        "creationTimestamp": "2025-07-01T13:38:01Z"
+      },
+      "spec": {
+        "description": "Enables use of app platform API for folders",
+        "stage": "experimental",
+        "codeowner": "@grafana/grafana-search-navigate-organise",
+        "frontend": true,
+        "hideFromAdminPage": true,
+        "hideFromDocs": true,
+        "expression": "false"
+      }
+    },
     {
       "metadata": {
         "name": "formatString",