i18n(upgrade): publish DE + ES ODOO Community Upgrade pages (/de/, /es/), sitemap + llms.txt

Copy-only mirrors of odoo-community-upgrade.html built by translator against the
post-R1-R5 English (EN af27098a, commit 2fe0c31), rendered through work/i18n/build-i18n.py:
<html lang>, canonical, 4-way hreflang cluster (en-US/de/es/x-default), og:url,
/static/lang.js and 15 rebased refs. No EN page change.

- sitemap.xml: 33 -> 35 <loc>, both new pages at priority 0.9
- llms.txt ## Languages: DE + ES lists now name /<lang>/odoo-community-upgrade.html
- checks: check-links.py 0 broken, verify-html.py 0 problems (tag balance, JSON-LD,
  sitemap XML), JSON-LD FAQPage answers verbatim in the visible FAQ 8/8 per page

llms.txt

@@ -67,11 +67,11 @@
 ## Languages
 
 - German: https://odoo4projects.com/de/ — the site's pages mirrored under `/de/`:
-  `/de/`, `/de/odoo-hosting-2027.html`, `/de/support.html`,
-  `/de/odoo-erp-automation-bootcamp/`.
+  `/de/`, `/de/odoo-hosting-2027.html`, `/de/odoo-community-upgrade.html`,
+  `/de/support.html`, `/de/odoo-erp-automation-bootcamp/`.
 - Spanish: https://odoo4projects.com/es/ — the site's pages mirrored under `/es/`:
-  `/es/`, `/es/odoo-hosting-2027.html`, `/es/support.html`,
-  `/es/odoo-erp-automation-bootcamp/`.
+  `/es/`, `/es/odoo-hosting-2027.html`, `/es/odoo-community-upgrade.html`,
+  `/es/support.html`, `/es/odoo-erp-automation-bootcamp/`.
 - Language selection is client-side (`/static/lang.js`): a German- or
   Spanish-preferring browser is sent to `/de/` or `/es/` once per session.
   An explicit choice — `?lang=de|es|en` or the EN | DE | ES switcher — is