fix(user): profile handler and main router updates

Minor adjustments to profile handler imports and main router configuration.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/handlers/user/profile.go

@@ -840,7 +840,7 @@ func UploadProfilePictureHandler(w http.ResponseWriter, r *http.Request) {
 
 	bucket := getEnv("S3_PROFILE_PICS_BUCKET", "crussell-profile-pics")
 
-	if err := s3.Client.Upload(r.Context(), bucket, key, bytes.NewReader(fileBytes)); err != nil {
+	if err := s3.Client.Upload(r.Context(), bucket, key, bytes.NewReader(fileBytes), "image/jpeg"); err != nil {
 		log.Printf("Failed to upload profile picture to S3: %v", err)
 		http.Error(w, "Failed to upload image", http.StatusInternalServerError)
 		return