v0.6.1

Added

• A spec-authoring loop convention. conventions.md now states the
  protocol for writing .keel/specs/<slug>/spec.md: draft one acceptance
  criterion, run keel gate g0 <slug>, fix only what the verdict names, and
  repeat until it passes. Written once in the store, it projects identically
  into CLAUDE.md, AGENTS.md, .kiro/steering/keel.md and
  .github/copilot-instructions.md, so the loop is the same regardless of
  which agent is driving.