Add missing comments to response.go and middleware.go for better code documentation

backend/internal/api/handlers/response.go

@@ -1,36 +1,44 @@
+// Package handlers provides HTTP request handlers for the API.
 package handlers
 
 import (
 	"github.com/gin-gonic/gin"
 )
 
+// Response is the standard JSON response format for all API endpoints.
 type Response struct {
 	Data  interface{} `json:"data"`
 	Error string      `json:"error,omitempty"`
 	Meta  *Meta       `json:"meta,omitempty"`
 }
 
+// Meta contains pagination information for list endpoints.
 type Meta struct {
 	Total int `json:"total,omitempty"`
 	Page  int `json:"page,omitempty"`
 }
 
+// JSON sends a response with the given status code and data.
 func JSON(c *gin.Context, status int, data interface{}) {
 	c.JSON(status, Response{Data: data})
 }
 
+// Error sends an error response with the given status code and message.
 func Error(c *gin.Context, status int, message string) {
 	c.JSON(status, Response{Error: message})
 }
 
+// Success sends a 200 OK response with the given data.
 func Success(c *gin.Context, data interface{}) {
 	JSON(c, 200, data)
 }
 
+// Created sends a 201 Created response with the given data.
 func Created(c *gin.Context, data interface{}) {
 	JSON(c, 201, data)
 }
 
+// NoContent sends a 204 No Content response.
 func NoContent(c *gin.Context) {
 	c.Status(204)
 }