chore: remove direct avatar upload endpoint (POST /profile/avatar);

feat: add endpoints for presigned upload URLs (GET /upload/avatar, GET /upload/image);
refactor: replace ProfileDto with NewProfileDto in update profile endpoint;
feat: implement S3 integration for avatar management;
fix: update database queries to handle new avatar upload flow;
chore: add new dependencies for S3 handling (golang.org/x/time);
refactor: rename UploadService to S3Service;
refactor: change return type for func LocalizeS3Url(originalURL string) (*url.URL, error);
feat: add custom validator for upload_id

sqlc/query.sql

@@ -285,9 +285,9 @@ SET
   name = COALESCE($2, name),
   bio = COALESCE($3, bio),
   birthday = COALESCE($4, birthday),
-  avatar_url = COALESCE($5, avatar_url),
-  color = COALESCE($6, color),
-  color_grad = COALESCE($7, color_grad)
+  avatar_url = COALESCE(sqlc.narg('avatar_url'), avatar_url),
+  color = COALESCE($5, color),
+  color_grad = COALESCE($6, color_grad)
 FROM users
 WHERE username = $1;