- New `slides +media-upload` shortcut: upload a local image to a slides
presentation and return the file_token for use in <img src="...">.
- `slides +create --slides` now supports `@./path.png` placeholders that
are auto-uploaded and replaced with file_tokens.
- Reject images >20 MB (multipart upload not supported for slide_file).
- Support wiki URL resolution for --presentation flag.