Add LSSHM to SSH tools list

[sannier3]

Summary

Adds [LSSHM](https://github.com/sannier3/lsshm) to the Tools section.

Why it should be included

LSSHM is a cross-platform local OpenSSH administration tool for Linux and Windows.

It provides a unified command-line interface for managing:

• The local OpenSSH server and its configuration
• Incoming access through authorized_keys
• Client SSH keys and ssh-agent
• Remote hosts through ~/.ssh/config
• Known host entries
• SSH security audits, backups and restoration

Unlike SSH session manager, which primarily manage remote connections, LSSHM also manages the local OpenSSH server and incoming access.

Potentially unsafe server configuration changes are validated before being applied. LSSHM also creates backups and provides automatic rollback when an operation fails.

The project is actively developed, documented in English and French, and includes automated build, syntax, checksum, unit and smoke tests.

Checklist

• I searched the README and previous pull requests for duplicates.
• The project is tested and documented.
• This pull request contains one suggestion.
• The entry links directly to the GitHub repository.
• The entry is added to the bottom of the relevant category.
• The description is short, descriptive and ends with a period.
• The change contains no trailing whitespace.