Spec Kitty

Mission Run: Coordination status log stays off the target branch

Keep a coordination mission's status log on its coordination branch from birth, so the target branch never carries it.

Creating a coordination-topology mission commits status.events.jsonl to the target branch in the scaffold commit. The status log is a coordination-partition artifact, so the later squash to the target fails with TARGET_BRANCH_CONTENT_CONFLICT (#5440). This mission seeds the status log on the coordination branch at create, keeps it out of the target-branch scaffold commit, and turns the red-first reproduction from PR #5518 green.