- Rename Append to Merge on Cookies, Headers, and Params types and simplify Parse to use direct append
- Replace strings_Join(sep, ...values) with slice_Join(slice, sep) for consistency with slice-based template functions
- Auto-enable quiet mode when stdout is not a terminal
- Remove ErrCLINoArgs check to allow running sarin without arguments
- Add -it flag to Docker examples in docs
- Add FileCache for caching local files and remote URLs in memory
- Update body_FormData to accept variadic key-value pairs with file support
- Use @ prefix for file paths (local or HTTP/HTTPS URLs)
- Use @@ to escape literal @ values
- Add file_Base64 function for Base64 encoding files
- Update documentation with new syntax and examples
