feat(seo): add /what-can-i-use-odoo-for/ guide page, linked from the homepage and support FAQ

Modelled on odoo-community-upgrade.html (top bar, band rhythm, FAQ details).
Copy published verbatim from the copywriter's 2026-10-28 file: 58-char title,
157-char meta, the six outbound internal links and the WebPage+Article+FAQPage+
BreadcrumbList @graph. Nine FAQ questions marked plausible-event-name=FAQ (no
event fires on page load). Sitemap + llms.txt list the new URL. Inbound links:
one from the homepage FAQ card, one from the support FAQ answer. Nothing else
moves; no footer change.

support.html

@@ -344,6 +344,7 @@
                                 <li><strong>Event company</strong>: Install Events and Website apps.</li>
                             </ul>
                             <p>No matter your business type, you can pick the apps that match your needs, and gradually build your Odoo system step by step.</p>
+                            <p>If the question you are asking is bigger than the apps — <em>what can I use Odoo for at all, and is it right for my kind of business?</em> — we have written that answer out properly, business type by business type: <a href="what-can-i-use-odoo-for/">what you can use Odoo for</a>.</p>
                         </div>
                     </div>
                     <div class="faq-item">