refactor: migrate from raw pgx to GORM, unify ErrNoRows, cleanup auth

internal/auth/middleware.go

@@ -11,19 +11,28 @@ func AuthMiddleware(jwtSecret []byte) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		authHeader := c.GetHeader("Authorization")
 		if authHeader == "" {
-			c.AbortWithStatusJSON(http.StatusUnauthorized, ErrorResponse{Error: "authorization header required"})
+			c.AbortWithStatusJSON(
+				http.StatusUnauthorized,
+				ErrorResponse{Error: "authorization header required"},
+			)
 			return
 		}
 
 		parts := strings.SplitN(authHeader, " ", 2)
 		if len(parts) != 2 || !strings.EqualFold(parts[0], "Bearer") {
-			c.AbortWithStatusJSON(http.StatusUnauthorized, ErrorResponse{Error: "invalid authorization header format"})
+			c.AbortWithStatusJSON(
+				http.StatusUnauthorized,
+				ErrorResponse{Error: "invalid authorization header format"},
+			)
 			return
 		}
 
 		claims, err := ValidateToken(parts[1], jwtSecret)
 		if err != nil {
-			c.AbortWithStatusJSON(http.StatusUnauthorized, ErrorResponse{Error: "invalid or expired token"})
+			c.AbortWithStatusJSON(
+				http.StatusUnauthorized,
+				ErrorResponse{Error: "invalid or expired token"},
+			)
 			return
 		}