feat(reporting): add researchReport executive summary layer (#34)

researchReport composes summaryTable, paretoChart, gainHistogram, held-out
gate decisions, and optional failureClusterView output into one structured
artifact for coding-vertical benchmark runs:

- promote/hold/reject decision with rationale, risks, next actions
- per-candidate stats (Wilcoxon q-value, Cohen's d, paired N, gain CI)
- Pareto frontier flagging
- markdown, HTML, and JSON chart specs

Wired into src/index.ts and the @tangle-network/agent-eval/reporting
subpath. Tests in tests/summary-report.test.ts cover decision logic,
candidate scoring, and output formats.

Author: drewstone

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## Unreleased
+
+### Added
+
+- `researchReport`, an executive research-report layer for coding-vertical
+  benchmark runs. Composes `summaryTable`, `paretoChart`, `gainHistogram`,
+  held-out gate decisions, and optional `failureClusterView` output into
+  promote/hold/reject guidance, risks, next actions, markdown, HTML, and JSON
+  chart specs.
+
 ## 0.20.10 — hardening audit follow-up
 
 ### Fixed

src/index.ts

@@ -735,6 +735,7 @@ export {
   summaryTable,
   paretoChart,
   gainHistogram,
+  researchReport,
 } from './summary-report'
 export type {
   SummaryTable,
@@ -745,6 +746,11 @@ export type {
   GainDistributionFigureSpec,
   GainDistributionBin,
   GainDistributionOptions,
+  ResearchReport,
+  ResearchReportOptions,
+  ResearchReportCandidate,
+  ResearchReportDecision,
+  ResearchReportRecommendation,
 } from './summary-report'
 
 export { runCanaries } from './canary'

src/reporting.ts

@@ -21,6 +21,7 @@ export type { RenderReleaseReportOptions } from './release-report'
 export {
   gainHistogram,
   paretoChart,
+  researchReport,
   summaryTable,
 } from './summary-report'
 export type {
@@ -29,6 +30,11 @@ export type {
   GainDistributionOptions,
   ParetoFigureSpec,
   ParetoPoint,
+  ResearchReport,
+  ResearchReportCandidate,
+  ResearchReportDecision,
+  ResearchReportOptions,
+  ResearchReportRecommendation,
   SummaryTable,
   SummaryTableOptions,
   SummaryTableRow,