Development record

`17-guard.md:483` says a file those tools write is judged only by where it lands in a shared main checkout, and anywhere else is written unchecked. `abcd guard hook` also denies a Write to a stop file or the shared-folder setting wherever it lands (`Write into the stop`, `internal/surface/cli/hook_occupancy.go:178`), and with `ABCD_STAGE_WRITES` set it denies a Write outside the stage and a Write to `Makefile` (`internal/surface/cli/hook_occupancy.go:156`).