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.

index.html

@@ -230,8 +230,7 @@
       .bf-topbar-cta{color:var(--brass);white-space:nowrap}
       .bf-topbar:hover .bf-topbar-cta,.bf-topbar:focus-visible .bf-topbar-cta{color:var(--brass-bright)}
     </style>
-    <link rel="stylesheet" href="style.css" media="print" onload="this.media='all'" />
-    <noscript><link rel="stylesheet" href="style.css" /></noscript>
+    <link rel="stylesheet" href="style.css" />
   <!-- Privacy-friendly analytics by Plausible -->
 <script async src="https://plausible.office.odoo4projects.com/js/pa-NhA7Rf-79VopXFQXhSS4e.js"></script>
 <script>
@@ -260,6 +259,7 @@
     </a>
 
     <!-- Hero -->
+    <main>
     <section class="hero">
       <div class="hero-notice" id="heroConfirmNotice" role="status" aria-live="polite" hidden>
         <i class="fas fa-check-circle" aria-hidden="true"></i>
@@ -649,6 +649,7 @@
     </section>
 
     <!-- Footer -->
+    </main>
     <footer class="footer">
       <div class="container">
         <div class="fgrid">