Add gitswitch under *SSH* agent

[OfirHaim1]

Adding gitswitch under ### *SSH* agent, alongside ssh-ident and sshecret which solve the same multi-identity problem from different angles.

* [gitswitch](https://github.com/target-ops/gitswitch) [![stars](https://img.shields.io/github/stars/target-ops/gitswitch.svg?style=social&label=stars)](https://github.com/target-ops/gitswitch) - Different SSH keys and git identities per directory, with a pre-commit hook that blocks wrong-author commits.

Why it fits this section

• Adds per-account SSH host aliases with IdentitiesOnly yes so ssh-agent doesn't broadcast every key in your keychain to every host (the privacy concern that motivates ssh-ident's existence).
• Plus binds git user.email/user.name/signing key + gh CLI account to the same directory, in lockstep, via a sentinel-marked includeIf block in ~/.gitconfig.
• Plus a pre-commit hook (gitswitch guard) that refuses commits where the active email doesn't match the directory's bound identity — the structural fix for "I committed as the wrong person."

Single Go binary, MIT licensed, ~2 MB, no runtime dependencies. macOS arm64/x64, Linux x64/arm64, Windows.