feat: add slider range validation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/utils/validators.ts

@@ -41,6 +41,17 @@ export function validateForm(
           errors.push({ fieldId: field.id, message: `${field.label} must be between 1 and 5.` });
         }
       }
+      if (field.type === 'slider') {
+        const n = Number(value);
+        const min = field.min ?? 0;
+        const max = field.max ?? 100;
+        if (isNaN(n) || n < min || n > max) {
+          errors.push({
+            fieldId: field.id,
+            message: `${field.label} must be between ${min} and ${max}.`,
+          });
+        }
+      }
     }
   }