Mission Run Overview
Mission Run: Trusted mission-artifact commit path
Make the coordination-branch bookkeeping commit path correct-by-construction so mission status/review artifacts can no longer silently diverge or block the loop.
Coordination-branch drift (#2841) and the review-claim actor leak (#2861) share one commit seam: mission artifacts get written to the wrong partition or with an invalid actor, then break at merge or block mid-flow. This mission routes every mission-artifact write through one placement port so a wrong-partition write is unrepresentable at commit, fixes the actor identity on the same path, stops the diff-compliance gate blocking a mission's own runtime state, and adds a non-blocking coord-staleness signal.