v5.0.0 — contexthub consolidation

Breaking

• Removed the forge and triage plugins. Their skills now live under contexthub:
  forge:<phase> → contexthub:<phase> (spec, plan, tdd, review, verify, debug, ship);
  triage:grade → contexthub:triage. No alias shims — reinstall contexthub.

Added

• Agent-aware graceful degradation: every multi-agent skill detects which of
  {Claude, codex, agy} are installed (new agent-availability.mjs) and runs the
  richest flow available, degrading to Claude-solo (with a note) instead of failing.
  contexthub now works with Claude alone — codex and agy are optional collaborators.

Changed

• contexthub is now the single multi-agent hub: full lifecycle (spec→ship), task
  triage, and the Delphi converge debate — 9 skills.
• Renamed forge-write.mjs → phase-write.mjs; lifecycle artifacts now under
  docs/carefully-crafted-plugins/lifecycle/.

Versions

• contexthub 3.0.1 → 4.0.0; marketplace 4.0.1 → 5.0.0. codex/agy unchanged.