Worktrees are created with `git worktree add --no-checkout` and populated
with `git reset --hard`, neither of which runs git's post-checkout hook.
Invoke the hook explicitly after population with git's standard arguments
(null ref previous HEAD, checked-out HEAD, flag 1) and the worktree as cwd,
mirroring `git worktree add` without --no-checkout.
A missing or non-executable hook is skipped (matching git) and a failing
hook is logged as a warning, never failing worktree creation or session
bootstrap. Applied to both the web server git service and the VS Code
runtime's git service.