fix: pre-action gate input handling for reliable pattern matching

fix: escape regex backslashes in gates.json

feat: add pre-action gates, post-compact re-injection, auto-failure tracking

docs: minor cleanup

fix: correct Hindsight bank creation payload and update GitHub username

fix: safer JSON encoding, remove CWD leak, pipe stdin for large payloads

feat: recall-stack - 5-layer Claude Code memory architecture