Codex 0.124.0 changed the required config.toml hooks format from the old
map-style ([hooks.shell]) to array-of-tables ([[hooks]]). Old GSD installs
that wrote the legacy format now cause a startup parse error on upgrade.
Add migrateCodexHooksMapFormat() which detects non-array [hooks] and
[hooks.TYPE] sections and rewrites them to [[hooks]] entries with an
injected type = "TYPE" key. The migration runs at the start of every Codex
install so affected configs self-heal on the next `gsd install --codex`.
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>