Image Tools - Added batch processing and image format conversion

A new "Image Format Conversion" tool has been added (local processing, no upload, supports batch WebP/JPG/PNG conversion), "Continue where you left off," and support for favorites ★ and recently accessed lists (localStorage). The Image Resizer preview now includes a Safe area overlay switch (suitable for 9:16 Story/Reels). New features include (batch resize + download zip + filename templates).