feat(staging): publish /odoo-staging-environment/ guide page

New standalone page answering 'odoo staging environment': what staging is,
how odoo.sh's staging branches work (sourced to odoo.sh's own docs and
pricing page), why most small businesses do not need one, and the
back-up-install-test route we offer instead.

- Built on the newest page pattern (top bar, band rhythm, hero, FAQ,
  language switcher, footer), page-scoped CSS only; no new framework.
- ICP review R1-R7 applied: backup plan-gate and slot limit stated,
  the 'ask us' claim resolved against the Side Hustle limit, the restore
  stated as a rollback of live work, the restore routed through support,
  the meta de-claims 'one-click ... safely', 'module' defined at first
  use, and a scope/price boundary added to the escalation.
- Title 51 chars, meta 148; one H1; six FAQ pairs byte-identical to the
  FAQPage JSON-LD; @graph WebPage+Article+FAQPage+BreadcrumbList parses.
- CTA -> support.html#contact (existing route). og:image reuses the
  established hero share image.
- sitemap.xml + one llms.txt line; blog/index.json untouched.

llms.txt

@@ -39,6 +39,7 @@
 - [ODOO x N8N Masterclass](https://odoo4projects.com/odoo-n8n-masterclass/): a two-hour live masterclass with Oliver Arnold on connecting Odoo to n8n — calling n8n webhooks from Odoo automated actions, how the n8n integration for Odoo works, and website workarounds that extend your automation. Hands-on in a free Odoo trial system; n8n itself runs on n8n's own free plan, which is not included. USD 120.00, next session the four Thursdays of February 2027 at 17:00 Central Time.
 - [ODOO Workshops and Classes](https://odoo4projects.com/workshops/): the two live courses side by side — the two-hour ODOO x N8N Masterclass (USD 120.00) and the ten-session ODOO ERP Automation Bootcamp (USD 465.00), both taught by Oliver Arnold — which course fits which business, and a full comparison table.
 - [What can I use Odoo for?](https://odoo4projects.com/what-can-i-use-odoo-for/): plain-English guide to what Odoo is used for — the ten apps and what each is for, what Odoo is used for by business type (manufacturing, retail and trade, services, construction, nonprofits, accounting practices, small business starting out), where it stops (Odoo Online will not take custom code, it will not do your trade's specialist work), what it costs, and how to start. Includes the nine-question FAQ.
+- [Odoo staging environment](https://odoo4projects.com/odoo-staging-environment/): what an Odoo staging environment is, how odoo.sh's staging branches work, why most small businesses do not need one, and the simpler back-up-install-test route we offer instead.
 - [Home](https://odoo4projects.com/): plans and pricing, FAQ, server locations.
 - [Support](https://odoo4projects.com/support.html): support and frequently asked questions.
 - [Legal](https://odoo4projects.com/legal.html): company details.