This PR adds a `!sysinfo` command to the bot that returns system information from the target machine.
- Windows: Uses `Get-ComputerInfo | ConvertTo-Json` (tested and works).
- Linux: Uses `uname -a` and `lsb_release -d` (untested).
- macOS: Uses `system_profiler SPHardwareDataType` (untested).
Output is automatically split into chunks of 1900 characters to avoid Discord message length limits, with each chunk sent as a separate code block.
Notes:
- The function avoids using `sendLongMessage` to prevent async/future compilation issues in Nim.
- Windows output is formatted as JSON. Linux and macOS outputs are plain text for now.
Testing is complete on Windows; Linux and macOS functionality remains to be verified.
