Plan-tune cathedral T3 (per D4 + Codex correction). The previous bin only
knew SessionStart and dedup'd on the hardcoded `gstack-session-update`
substring. The cathedral needs PreToolUse + PostToolUse hooks registered
side-by-side with the user's own hooks, with explicit consent UX, backups,
and rollback.
New subcommands:
- add-event --event <SessionStart|PreToolUse|PostToolUse|...> --command <cmd>
--source <tag> [--matcher <re>] [--timeout <s>]
- remove-source --source <tag> # removes all entries tagged by source
- diff-event ... # preview without mutating
- rollback # restore latest backup
- list-sources # audit gstack-tagged hooks
Multi-source dedup via a new `_gstack_source` field on each hook entry
(Claude Code preserves unknown fields). Source tag lets plan-tune-cathedral
register PreToolUse + PostToolUse without colliding with the existing
SessionStart wiring, and lets remove-source clean up cleanly during
gstack-uninstall.
Backups written automatically to settings.json.bak.<ts> before any
mutation, with a .bak-latest pointer the rollback subcommand reads.
Existing legacy `add <cmd>` / `remove <cmd>` shape preserved verbatim so
setup --team and gstack-uninstall keep working unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Garry Tan