Merge One Skill-Pair

Execute a single skill-pair merge as one atomic commit. This skill is the execution unit that zj-merge-skills-wave delegates to.

Pre-condition

A roadmap node must already exist with a decisions entry containing:

• the strategy (strict-align / absorb / adopt / replace / reject)
• the source path (or URL → scratch path)
• the base path (or null if source is new to base)

If no node exists, route to zj-merge-skills-wave first.

Side-effect checklist

Before writing the file-level plan, read the side-effect checklist. A correct merge touches whichever subset is in scope, never just SKILL.md.

Source preservation gate