quantmodel — Add common-window correlation matrix to comparison workspace

Objective

Add common-window correlation matrix to comparison workspace.

Notes: Added tested common-window Pearson matrix in selection order, with 1.000 diagonals for variable series, explicit zero-variance unavailable cells, responsive table rendering, and stale-output clearing.

Approach

Reuses existing report research/findings/comparison-correlations-t232.md — tables/metrics preserved verbatim via source_report pointer. Body below summarizes grounded evidence from that report and adjacent artifacts.

Files / code / data changed

No commit SHA confidently associated with t232 in sampled log [reconstructed — uncertain].
Source report: research/findings/comparison-correlations-t232.md
Task-history entry: research/findings/task-history.json#t232

Results

Conclusions and metrics are in research/findings/comparison-correlations-t232.md; see detail page for preserved tables/metrics.

Conclusions

[reconstructed — uncertain] Outcome inferred from status done and task note.

Problems / follow-ups

See source report or PR discussion for follow-ups. No unsupported follow-ups fabricated.