使用了AI重构项目，并完善了一部分后台问题

internal/api/validation.go

@@ -0,0 +1,32 @@
+package api
+
+import (
+	"net/url"
+	"path"
+	"strings"
+)
+
+func validHTTPURL(value string) bool {
+	parsed, err := url.ParseRequestURI(strings.TrimSpace(value))
+	return err == nil && parsed.Host != "" && (parsed.Scheme == "http" || parsed.Scheme == "https")
+}
+
+func validContactURL(value string) bool {
+	value = strings.TrimSpace(value)
+	parsed, err := url.ParseRequestURI(value)
+	if err != nil {
+		return false
+	}
+	if parsed.Scheme == "http" || parsed.Scheme == "https" {
+		return parsed.Host != ""
+	}
+	return parsed.Scheme == "mailto" || parsed.Scheme == "tel"
+}
+
+func validQRCode(value string) bool {
+	value = strings.TrimSpace(value)
+	if strings.HasPrefix(value, "/uploads/") {
+		return !strings.Contains(value, "\\") && path.Clean(value) == value
+	}
+	return validHTTPURL(value)
+}