refactor: standardise S3 URL generation (#362)

* refactor: replace presigned URL uploads with backend upload endpoints

* feat: update avatar upload to use new endpoint

* refactor: use createS3Client in auth hooks

* feat: generate presigned URLs for avatars

* fix: show avatar image in user menu

* fix: hide tooltip if content is empty

* fix: support external avatar URLs in generateAvatarUrl

* fix: remove content type restriction on attachments

packages/shared/src/utils/index.ts

@@ -3,3 +3,4 @@ export * from "./generateSlug";
 export * from "./subscriptions";
 export * from "./email";
 export * from "./dueDateFilters";
+export * from "./s3";