Merge pull request #13570 from backstage/freben-dschwank/user-settings-backend

feat: add user-settings-backend and related frontend store

packages/core-app-api/api-report.md

@@ -556,7 +556,9 @@ export class WebStorage implements StorageApi {
   // (undocumented)
   get<T>(key: string): T | undefined;
   // (undocumented)
-  observe$<T>(key: string): Observable<StorageValueSnapshot<T>>;
+  observe$<T extends JsonValue>(
+    key: string,
+  ): Observable<StorageValueSnapshot<T>>;
   // (undocumented)
   remove(key: string): Promise<void>;
   // (undocumented)

packages/core-app-api/src/apis/implementations/StorageApi/WebStorage.ts

@@ -86,7 +86,9 @@ export class WebStorage implements StorageApi {
     this.notifyChanges(key);
   }
 
-  observe$<T>(key: string): Observable<StorageValueSnapshot<T>> {
+  observe$<T extends JsonValue>(
+    key: string,
+  ): Observable<StorageValueSnapshot<T>> {
     return this.observable.filter(({ key: messageKey }) => messageKey === key);
   }