feat(staging): inbound links so /odoo-staging-environment/ is not an orphan

The copy's 'Into this page' table, applied as single additive sentences:
- support.html: the 'error 500 after a git check in' FAQ answer links
  'test it safely first'.
- blog/posts/speed-run-backup.html: end of the post links
  'what a staging environment is, and why you probably do not need one'.
- odoo-hosting-2027.html: one contextual note by the backup/module rows
  links 'do you need a staging environment?'.
- index.html: one FAQ card 'Do you need an Odoo staging environment?'.
No footer change. No new impeccable finding category.

index.html

@@ -382,6 +382,10 @@
             <div class="faq-q"><span>ODOO Community? What can it do?</span> <i class="fas fa-chevron-down"></i></div>
             <div class="faq-a"><p>Inventory, accounting, CRM, sales, manufacturing, HR — all in one system. Free and fully open-source. <a href="what-can-i-use-odoo-for/">What you can use Odoo for, in plain English</a>.</p></div>
           </div>
+          <div class="faq-card plausible-event-name=FAQ" onclick="this.classList.toggle('open')">
+            <div class="faq-q"><span>Do you need an Odoo staging environment?</span> <i class="fas fa-chevron-down"></i></div>
+            <div class="faq-a"><p>Most small businesses do not. If you change Odoo's code you do; if you install a finished module, a backup and a careful test is enough. <a href="odoo-staging-environment/">Do you need an Odoo staging environment?</a></p></div>
+          </div>
           <div class="faq-card plausible-event-name=FAQ" onclick="this.classList.toggle('open')">
             <div class="faq-q"><span>Do you have an affiliate program?</span> <i class="fas fa-chevron-down"></i></div>
             <div class="faq-a"><p>No. We believe it is in our best interest to have competitive prices for our shared clients.</p></div>