Gate finding (High, 2ab): dropping --force from the startup reap's
`git worktree remove` makes git read the tree's index, which executes the
repository's core.fsmonitor (GHSA-7x36-8jrh-v4pw) on the unattended
startup sweep. tests/security/test_gitspawn_config_injection.py went red.
Route the remove through noninteractive_repo_git_env(entry) +
stdin=DEVNULL, the same pattern as _worktree_is_dirty; when the env
cannot be built, keep the tree. Extend the security test to also drive
the attended reclaim_worktrees remove (worktree_gc._git already uses the
safe env) so both plain-remove paths are pinned.
5a4b350480