Fix/enable worktrees sui precommit

[paulusrex]

Description

This PR fixes an issue with sui-precommit when working with Git worktrees checking if we are working on a worktree directory and adjust the paths accordingly.

Git worktrees allow developers (and AI agents) to run multiple branches in parallel on the same machine. Since sui-precommit was developed when this feature was less common, the tool previously assumed the working directory was always a standard repository root and not a worktree.

Review steps

git worktree add ../sui-repo.worktrees/hotfix-branch -b hotfix-branch
cd ../sui-repo.worktrees/hotfix-branch
npm install

now
Inside a repo with sui-mono and sui-precommit will fail

after change
The npm install will suceed

Manual checks

I manually did these checks installing my local modified package and create a worktree:

• Install on worktree works fine
• Install on main repo works fine
• sui-mono commit works fine on main and worktree repo.
• sui-mono commit-all works fine on main and worktree repo.