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>

lib/guard.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# guard.sh — Active-state guard for cron entry points
+# guard.sh — Active-state guard for polling-loop entry points
 #
 # Each agent checks for a state file before running. If the file
 # doesn't exist, the agent logs a skip and exits cleanly.