docs: Phase 14 — Last reviewed line sweep across docs/

Per Phase 1 audit at cowork/docs-overhaul-phase-1-audit-2026-05-04/.
Adds a `> Last reviewed: 2026-05-05` line right after the H1 heading
of every doc that didn't already have one (41 files).

This dates the freshness clock for the future Phase 4 per-doc review.
The discipline going forward: when a doc's content gets a meaningful
edit, bump the date. When the date gets old (e.g., >6 months), the
doc earns a freshness-review pass.

Mechanical insertion via awk one-liner, applied to every docs/*.md
that didn't already match `grep -q 'Last reviewed:'`. Files that
already carried the line from earlier Phase 2 work (the navigation
index, the new connector docs, the new SCEP server / legacy-clients-
TLS-1.2 / release-verification docs, and the 5 per-connector deep
dives) were skipped to avoid duplicate insertion.

Net: every doc in docs/ now has a Last reviewed line.

docs/contributor/ci-pipeline.md

@@ -1,5 +1,7 @@
 # CI Pipeline — Operator Guide
 
+> Last reviewed: 2026-05-05
+
 > Authoritative guide to certctl's CI pipeline shape.
 > Per `cowork/ci-pipeline-cleanup-prompt.md` Phase 12.
 

docs/contributor/qa-test-suite.md

@@ -1,5 +1,7 @@
 # QA Test Suite Guide (`qa_test.go`)
 
+> Last reviewed: 2026-05-05
+
 > **Audience:** Anyone running release QA for certctl — whether you're a first-time contributor or the maintainer cutting a release tag.
 >
 > **Companion to:** `docs/testing-guide.md` (the *what* to test). This document explains the *how* — the automated test file, what it covers, what it skips, and how to fill the gaps manually.

docs/contributor/test-environment.md

@@ -1,5 +1,7 @@
 # certctl Testing Environment
 
+> Last reviewed: 2026-05-05
+
 A step-by-step guide to running certctl locally with real certificate authorities. Every command is spelled out. Every expected output is shown. If something goes wrong, the troubleshooting section tells you exactly what to check.
 
 ---

docs/contributor/testing-strategy.md

@@ -1,5 +1,7 @@
 # certctl Testing Strategy & Deep-Scan Operator Runbook
 
+> Last reviewed: 2026-05-05
+
 This doc covers the **testing topology** (per-PR fast gates vs. daily deep-scan
 gates), and the **operator runbook** for re-running each deep-scan tool locally
 when the CI receipt is ambiguous or when an operator wants to validate a fix