Note upstream PR #5 (microplex fix/shared-col-categorical-noise) in session summary

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: MaxGhenis

docs/overnight-session-2026-04-16.md

@@ -130,6 +130,7 @@ After the stage-1 evidence landed, I continued with the open items:
 6. **Quickstart doc** (`docs/quickstart-rewire.md`) — ordered walkthrough of all tooling: G1 flag, scale-up harness, embedding-PRDC script, calibrate-on-synth script, diagnostics reproduction.
 7. **Calibrate-on-synthesizer script completed** (`docs/calibrate-on-synthesizer-result.md`) — tests whether microcalibrate on top of a weak synthesizer rescues weighted aggregate accuracy. **ZI-QRF pre-cal 0.26 → post-cal 0.14 mean relative error; ZI-MAF pre-cal 17.98 → post-cal 15.08 (still useless).** Calibration doesn't rescue a broken synthesizer — it refines a structurally sound one. Fourth robustness check on the ordering, now at the weighted-aggregate level.
 8. **Upstream bug found + mitigated** (`docs/per-column-zero-rate-bug.md`, `docs/stage-1-post-snap-results.md`) — `microplex.eval.benchmark._MultiSourceBase.generate` adds σ=0.1 Gaussian noise to every shared-column value including binary/categorical ones. Harness now snaps synthetic values back to the training-pool grid for any integer-valued shared column. **Post-snap stage-1 coverage at 77k × 50: ZI-QRF 0.928, ZI-QDNN 0.707, ZI-MAF 0.106.** Numbers are much higher than the pre-snap stage-1; ordering is preserved. The G1 cross-section with ZI-QRF produces 92.8 % PRDC coverage — production-credible.
+9. **Upstream fix PR filed**: microplex PR #5 on branch `fix/shared-col-categorical-noise`. Detects integer-valued columns in the training pool and skips noise injection for them. Core test suite passes unchanged (658 passed, 68 skipped, 2 xfailed). Once merged, microplex-us's local snap mitigation becomes a no-op.
 8. **Method-kwargs config** — `ScaleUpStageConfig.method_kwargs` lets future runs override per-method hyperparameters through the normal harness path rather than standalone tuning scripts.
 
 Updated PR #3 count: **20 commits**, all green tests, all pushed. Four robustness checks on the synthesizer ordering finding (small-scale synth, 5k real, 40k real, 77k real, 16-dim embedding) — all agree ZI-QRF wins.