feat: remove authentication requirement for avatar and image upload endpoints;

fix: remove 500 error responses from upload endpoints;
fix: return validation error strings instead of error lists;
fix: handle invalid avatar upload IDs with 400 Bad Request response;
fix: add missing S3Controller to controller initialization;
fix: change avatar_upload_id to string type and update validation rules;
chore: add license header to smtp.go;
refactor: replace manual proxy implementation with httputil.ReverseProxy;
fix: inject S3Service dependency into ProfileService;
fix: set color and color_grad fields during profile update;
fix: correct DTO mapping for profile and settings;
fix: check object existence before copying in SaveUpload;
fix: adjust profile DTO mapping function for proper pointer handling

backend/internal/controllers/profile.go

@@ -81,7 +81,6 @@ func NewProfileController(_log *zap.Logger, _ps services.ProfileService) Control
 	}
 } 
 
-// XXX: untested
 //	@Summary Get your profile
 //	@Tags Profile
 //	@Accept		json
@@ -100,7 +99,6 @@ func (ctrl *ProfileController) getMyProfile(c *gin.Context) {
 	c.JSON(http.StatusOK, response)
 }
 
-// XXX: untested
 //	@Summary Get profile by username
 //	@Tags Profile
 //	@Accept		json
@@ -131,12 +129,8 @@ func (ctrl *ProfileController) getProfileByUsername(c *gin.Context) {
 	}
 
 	c.JSON(http.StatusOK, response)
-
-	print(cinfo.Username)
-	panic("Not implemented")
 }
 
-// XXX: untested
 //	@Summary Get your profile settings
 //	@Tags Profile
 //	@Accept		json
@@ -155,7 +149,6 @@ func (ctrl *ProfileController) getProfileSettings(c *gin.Context) {
 	c.JSON(http.StatusOK, response)
 }
 
-// XXX: untested
 //	@Summary Update your profile
 //	@Tags Profile
 //	@Accept		json
@@ -169,7 +162,12 @@ func (ctrl *ProfileController) updateProfile(c *gin.Context) {
 		return
 	}
 
-	response, err := ctrl.ps.UpdateProfile(request.User, request.Body); if err != nil || !response {
+	response, err := ctrl.ps.UpdateProfile(request.User, request.Body); if err != nil {
+
+		if errors.Is(err, errs.ErrFileNotFound) {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid upload ID. Make sure file was uploaded and is not expired."})
+		}
+
 		c.Status(http.StatusInternalServerError)
 		return
 	}
@@ -177,7 +175,6 @@ func (ctrl *ProfileController) updateProfile(c *gin.Context) {
 	c.JSON(http.StatusOK, response)
 }
 
-// XXX: untested
 //	@Summary Update your profile's settings
 //	@Tags Profile
 //	@Accept		json