tools: add binary file support with hexdump display (#4331)

* tools: add binary file support with hexdump display

Adds support for reading and displaying binary files in the read file tool
with a hexdump-formatted view. This enables better handling of binary content
in the IDE context without attempting to interpret them as text.

- Adds hexdump utility to format binary data in a readable hex/ASCII view
- Extends readFileTool to detect binary files and provide formatted output
- Adds binaryFileHexdump prompt component for displaying binary content
- Integrates binary file variable support in file variable display
- Updates test fixtures with binary file handling scenarios

Fixes https://github.com/microsoft/vscode/issues/284178
Fixes https://github.com/microsoft/vscode/issues/299973

(Commit message generated by Copilot)

* pr comments

* baseline update

* baseline update