Split 1/3 of #829, carved out as the independently-reversible hardening layer
with no dependency on the orchestration work that stacks on top of it.
- internal/pathjail: os.Root handle-relative path confinement — ancestor
traversal is confined, the final component is checked for reparse points
(including a name written with a trailing separator), unprivileged Windows
junctions are covered, temp-name fragments are rejected before they can
escape the directory, whitespace-bearing paths are confined as spelled, and
temp files stay unpredictable and exclusive.
- internal/credstore: file locking around the credential read-modify-write —
exclusive for writers, shared for readers, so a reader cannot race a publish.
- internal/worktrees: git invocation hardening.
pathjail has no importers in this PR by design; internal/memory and
internal/specialist adopt it in the stacked PRs (2/3 and 3/3).
Origin-Session: local-de382f | Claude Code | 4 prompts
Origin-Snapshot: 52db9b74dad5
Co-authored-by: Claude Opus 4.8 <[email protected]>
