perf(site-wide): render-blocking /style.css on 17 pages; <main> landmark; BF footer form action

Same defect the bootcamp carried (2aa9b19), fixed site-wide in one mechanical pass.

P0 (17 pages): /style.css was deferred via media="print" onload=... -> unstyled
first paint -> a BODY layout shift. Now a normal render-blocking
<link rel="stylesheet">; the now-redundant no-JS <noscript> for style.css is
dropped. Web fonts + Font Awesome keep their legitimate deferral.
Pages: index.html, odoo-black-friday/, odoo-hosting-offers/, de/index.html,
es/index.html, odoo-hosting-2027.html (+de/+es), odoo-community-upgrade.html
(+de/+es), odoo-staging-environment/, odoo-community-ai/,
odoo-n8n-masterclass/, australia.html, workshops/, what-can-i-use-odoo-for/.

P1 (1 page): /odoo-black-friday/ footer form action mailto: -> CRM webhook
(Lighthouse is-on-https). Changed only because the page already loads a handler
for #footerContactForm (static/black-friday.js). The other 13 mailto-form pages
load no handler and are left alone on purpose (no drive-by handler copy-in).
Added the no-JS <noscript> fallback so a JS-off visitor keeps a path.

P2 (35 pages): add a single <main> landmark wrapping the primary content; top
bar and footer stay outside. Additive only, no redesign.

Guards held: bootcamp EN/DE/ES and every JS/static file untouched; Buy forms
product_id 4/17 intact; one [data-bc-seats]; ads-consent gate intact.
verify-html.py PROBLEMS 0; competitor QC 74 pre-existing, 0 added.

blog/posts/odoocommunity-agents.html

@@ -173,6 +173,7 @@
 </script>
     </head>
     <body>
+        <main>
         <div class="container" style="width:80%; max-width:800px; margin:0 auto; padding:0 20px;">
             <div class="blog-header">
                 <a href="../../index.html#blog">&larr; Back to Blog</a>
@@ -309,6 +310,7 @@
                 <a href="../../index.html#blog">&larr; Back to all posts</a>
             </div>
         </div>
+        </main>
         <script defer src="/static/agent-odoo4projects/agent.js"></script>
     </body>
 </html>