Replace the commiter subagent with a create-commit skill,
consistent with the create-pr and create-issue skill patterns.
- Remove .opencode/agents/commiter.md
- Add .opencode/skills/create-commit/SKILL.md
- Update implement-plan.md to use the skill instead of
subagent delegation
- Document commit body line wrapping at 72 chars in
creating-commits memory and skill
AI-assisted-by: mimo-v2.5
