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>

.woodpecker/agent-smoke.sh

@@ -102,9 +102,9 @@ echo "=== 2/2  Function resolution ==="
 #   lib/load-project.sh     — sourced by env.sh when PROJECT_TOML is set
 #   lib/file-action-issue.sh — sourced by gardener-run.sh (file_action_issue)
 #   lib/secret-scan.sh      — sourced by file-action-issue.sh (scan_for_secrets, redact_secrets)
-#   lib/formula-session.sh  — sourced by formula-driven agents (acquire_cron_lock, check_memory, etc.)
+#   lib/formula-session.sh  — sourced by formula-driven agents (acquire_run_lock, check_memory, etc.)
 #   lib/mirrors.sh          — sourced by merge sites (mirror_push)
-#   lib/guard.sh            — sourced by all cron entry points (check_active)
+#   lib/guard.sh            — sourced by all polling-loop entry points (check_active)
 #   lib/issue-lifecycle.sh  — sourced by agents for issue claim/release/block/deps
 #   lib/worktree.sh         — sourced by agents for worktree create/recover/cleanup/preserve
 #