Module writer 

File-write helpers used by the marketplace install. Writes are content-addressed (skip when bytes match) so re-running gw setup-claude is a true no-op when nothing changed.

Functions

sentinel_present

write_if_changed

Write content to path. If the file already exists with byte-identical content, do nothing. Returns true if a write actually occurred. Creates any missing parent directories.

write_sentinel

Drop a sentinel marker that lets future gw setup-claude runs (and the legacy-cleanup step) recognize a directory we own.