Repair the measurement pipeline
All seven deliverables in §2. Historical records stay as they are — the fix is prospective; the effort report may add a schema-version guard when reading old shapes.
/reckon-ship run-measurement-truth
All seven §2 deliverables landed across commits fe1497f, 2b1acae and 0d97517, plus a corrective labelled duration-fallback for the timestamp-less-stream finding: stream-derived durations with stall exclusion and labelled sources, per-run token/cost deltas summing to session cumulatives, one completion-source vocabulary with provided, outcome refusal on non-pass, tmpfs manifest warnings, typed changed-lines, canonical section identifiers and redispatch lineage. Historical records untouched (prospective fix as planned). Sprint gate measures all produced. done — no followup