* fix(gateguard): gate force/path git checkout as destructive
The destructive-command gate's `checkout` handler only flagged
`git checkout -- <path>`. It missed `git checkout --force` / `-f <branch>`
and `git checkout .`, all of which discard uncommitted working-tree changes,
so they bypassed the gate (once the once-per-session routine-Bash gate is
satisfied, they ran with no challenge). The sibling `switch` handler already
covers these force forms; mirror it for `checkout`.
* test(gateguard): document Test 7b force-checkout case
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Co-authored-by: bymle <229636660+bymle@users.noreply.github.com>