Representation study — bitmap vs selection vector

Status: OPEN — pre-registered; one-ISA indicative slice only. The full study needs entry-referenced ledger data across ≥3 ISAs and ≥5 µarchs (Charter §6.2 / Survey §11.3 #3); only apple-m2-mba is registered (risk R-06 / REQ-LEDGER-012), so the cross-µarch analysis and conclusion are PENDING hardware. No numbers here are invented (Charter T2).

This directory is the M9 charter deliverable — the bitmap-vs-selvec representation question, its pre-registered method, the data collected so far, and the analysis/conclusion (open):

File	Contents
question.md	The research question and hypotheses
method.md	Pre-registered protocol + decision rule (run before looking at cross-µarch data)
entries.md	Data: the apple-m2 (NEON) indicative slice; the ≥3-ISA/≥5-µarch ledger entries are pending
analysis.md	Analysis of the slice; what the full study still requires
conclusion.md	OPEN — cannot be drawn from one µarch

Gate: releases/gates/M9.md.