fix: 4 chain bugs found via /selftest+ chain audit

fix: discoverer crash + speed up + auto-keyword harvest + agentic re-seed

fix: 3 critical issues — dataset privacy, crawler pollution, offset reset

fix: strip Mac /usr/bin/* hardcoded paths + expand dataset-enrich to 21 sources

feat: migrate $HOME/.claude/* to $HOME/.surrogate/* (clean separation from Claude Code)

feat: parallel orchestrate + agentic crawler + skill synthesis + 3-min sync