Mission Run Overview
Mission Run: Read-Side Placement-Seam Migration
Every mission-artifact read routes through the placement seam (as writes already do), with a fail-closed gate so new bypasses cannot land — closing the read-side half of the placement port.
Mission artifacts live on partitioned branches; a read must resolve the correct partition and artifact kind through a single seam. Today roughly 50-64 modules bypass that read seam by calling kind-blind resolvers directly — the read-side twin of the write-side split-brain a prior mission already closed. This mission routes those reads through the seam and adds a fail-closed architectural gate symmetric to the write-side one, so the read path has one authority and drift cannot recur. It also folds in a fix for a frontmatter-corruption bug in the lane-mismatch repair path (#2921).