Add bias-audit module: cohort-provenance + method-ceiling diagnostics

Implements six new exports for circulating-miRNA biomarker QC:
- os_bias_floor_auc: dataset-identity-only classifier AUC
- os_covariate_only_auc: single-covariate classifier AUC (age, sex, storage)
- os_per_feature_batch_signal: healthy-only ANOVA for batch confounding
- os_clustered_bootstrap_auc: clustered CI respecting specimen duplicates
- os_detect_cross_cohort_duplicates: cross-GSE OV-code crosswalk
- os_bias_audit: top-level orchestrator with print.os_bias_audit method

All six functions are generic enough for any omics dataset and do not
depend on miRNA specifics. 14 testthat cases cover asymmetric cohort,
age-confound, feature-batch-signal ranking, clustered-vs-naive bootstrap
width, cross-cohort dup detection, and orchestrator integration.

Motivated by the 2026-04-18 miRPOC OC meta-analysis, which showed that
a cohort-identity classifier reaches AUC 0.72 on four public 3D-Gene
consortium cohorts before any biomarker feature is used, and that
matching cases and controls on institution and storage collapses the
apparent 14-panel AUC from 0.95 to 0.74.

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

Author: kstawiski

NAMESPACE

@@ -14,6 +14,7 @@ S3method(print,OmicSelectorGoldStandard)
 S3method(print,OmicsInput)
 S3method(print,ReportData)
 S3method(print,SignatureSelectionResult)
+S3method(print,os_bias_audit)
 S3method(print,ws_perturbation_benchmark)
 export(BenchmarkService)
 export(CrossPlatformAdapter)
@@ -130,6 +131,12 @@ export(merge_omics_data)
 export(noise_augment)
 export(omic_benchmark)
 export(omic_pipeline)
+export(os_bias_audit)
+export(os_bias_floor_auc)
+export(os_clustered_bootstrap_auc)
+export(os_covariate_only_auc)
+export(os_detect_cross_cohort_duplicates)
+export(os_per_feature_batch_signal)
 export(partial_dependence)
 export(plot_signature_tradeoffs)
 export(plot_xai_importance)

NEWS.md

@@ -1,3 +1,8 @@
+# OmicSelector 2.3.0
+
+- Added bias-audit module (6 exported functions) for cohort-provenance and
+  method-ceiling diagnostics.
+
 # OmicSelector 2.2.0
 
 - Added the Paper 1 v2.2 within-sample biomarker panel methods: CLR transforms,