fix: tech-debt: sweep cron-isms from code comments, helpers, lib, and public site copy (#548)

- Rename acquire_cron_lock → acquire_run_lock in lib/formula-session.sh
  and all five *-run.sh call sites
- Update all *-run.sh file headers: "Cron wrapper" → "Polling-loop wrapper"
- Rewrite docs/updating-factory.md: replace crontab check with pgrep,
  replace "Crontab empty after restart" section with polling-loop equivalent
- Update docs/EVAL-MCP-SERVER.md to reflect polling-loop reality
- Update lib/guard.sh, lib/AGENTS.md, lib/ci-setup.sh comments
- Update formulas/*.toml comments (cron → polling loop)
- Update dev/dev-poll.sh usage comment
- Update tests/smoke-init.sh to handle compose vs bare-metal scheduling
- Update .woodpecker/agent-smoke.sh comments
- Update site HTML: architecture.html, quickstart.html, index.html
- Clarify _install_cron_impl is bare-metal only (compose uses polling loop)
- Keep site/collect-engagement.sh and site/collect-metrics.sh cron refs
  (genuinely cron-driven on the website host, separate from factory loop)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

formulas/run-publish-site.toml

@@ -216,7 +216,7 @@ Check 3 — engagement evidence has been collected at least once:
     jq -r '"  visitors=\(.unique_visitors) pages=\(.page_views) referrals=\(.referred_visitors)"' "$LATEST" 2>/dev/null || true
   else
     echo "NOTE: No engagement reports yet — run: bash site/collect-engagement.sh"
-    echo "The first report will appear after the cron job runs (daily at 23:55 UTC)."
+    echo "The first report will appear after the scheduled collection runs (daily at 23:55 UTC)."
   fi
 
 Summary: