- escapePath now returns an error when paths contain dot-segments
(".", "..") instead of silently rewriting them. This prevents
subtle API misses where callers pass "foo/../bar" expecting to
hit "bar" but the old code produced "foo/bar".
- Uses path.Clean for canonical form after validation.
- CommitStatus.Description for check runs is now empty string
instead of the raw conclusion enum. The conclusion is already
captured in the Status field via mapCheckRunStatus; storing it
again in Description was semantically inconsistent with commit
statuses where Description carries a human-readable narrative.
- Removed unused derefString helper.
- Added tests for escapePath valid paths, dot-segment rejection,
and GetFileContentAtRef dot-segment error propagation.
claw