Mission Run Overview
Mission Run: Verdict-matrix RMW preservation (acceptance #4858 + issue #4868)
Stop verdict-recording commands from silently dropping previously-committed matrix rows and flipping outcomes, on coordination and flat layouts.
Two verdict-recording flows can silently erase prior rows from their coordination-resident matrix and exit success. Recording an acceptance verdict concurrently for a different invariant overwrites the whole acceptance matrix from a stale pre-check snapshot, flipping the overall verdict fail to pass (#4858). Recording an issue verdict on a coord mission migrates the wrong source directory on the first JSON write, so existing issue verdicts vanish from active state (#4868). Both are verdict-matrix read-modify-write preservation failures: a verdict write must be based on the true authoritative current matrix and change only the row it owns. This mission closes that class across both matrices.