- Changed Gallery.gohtml to remove restriction on PNG uploads.
- Updated upload button text to "Upload Anything"

feat: implement new upload handler

- Implemented uploadHandler to handle file uploads.
- Uses eagle.ItemAddFromPath to upload files to Eagle.
- Includes error handling for file size, parsing, and Eagle upload failures.
- Adds a temporary file with a 30-second delay before deletion to avoid race conditions.
- uploadHandlerOld is left in, but unused.

feat: conditionally disable upload route

- Added a command-line flag `--block-upload` to disable the `/upload` route.
- Displays a warning message when `/upload` is enabled, indicating potential security risks.