[EPIC] docs hardening audit (F2 round)

gh issue create --title "[EPIC] docs hardening audit (F2 round)" --label "epic,audit" --body "## EPIC: docs hardening audit (F2 round)

Source: F2 audit round, 2026-09-03. This EPIC aggregates the 10 findings from the docs audit (3 HIGH, 4 MEDIUM, 3 LOW).

HIGHs include CHANGELOG link-reference drift (resolved-async). MEDIUMs include README and ROADMAP staleness. LOWs include a stray @master reference and a CHANGELOG Unreleased artifact (already fixed).

### HIGH

- [ ] #234 docs H1 — SECURITY.md 'Currently maintained' latest version (CLOSED, fixed by 858de77)
- [ ] #235 docs H2+H3 — CHANGELOG missing link-references for v2.11.0 and v2.11.1; duplicates

### MEDIUM

- [ ] #236 docs M1 — README extended example has broken YAML indentation
- [ ] #237 docs M2 — CHANGELOG v1.3.3 placeholder date 2024-XX-XX
- [ ] #238 docs M3+M4 — ROADMAP stale; inputs count off

### LOW

- [ ] #141 runbook needs updating for protect-main ruleset (existing; F2 added 2 sub-gaps, also in workflows EPIC)
- [ ] #239 docs L2 — README ASCII art mentions @master not @main
- [ ] #240 docs L3 — CHANGELOG Unreleased contained v2.11.2 entry (CLOSED, fixed by PR #170)

## Suggested resolution order

1. Land H2+H3 in v2.11.3 — link-reference cleanup is mechanical and the doc-render bug is user-visible.
2. Batch M1+M2+M3+M4 into a v2.11.4 doc-cleanup release.
3. LOWs into a later cleanup.

## Source

F2 audit 2026-09-03 (docs audit). Reporter: subagent-pekodbj7."