feat(analytics): add cookieless Cloudflare Web Analytics beacon

Adds the Cloudflare Web Analytics beacon to every page (injected in
GA_LINES alongside the GA tag). Cookieless and consent-free, so it
counts all visitors regardless of the cookie banner — complements GA4,
which only records consented sessions.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/seo_inject.py

@@ -194,6 +194,8 @@ GA_LINES = [
     f"      gtag('config', '{GA_ID}');",
     '    </script>',
     '    <script src="/consent.js" defer></script>',
+    '    <!-- Cloudflare Web Analytics (cookieless, no consent needed) -->',
+    "    <script type=\"module\" src=\"https://static.cloudflareinsights.com/beacon.min.js\" data-cf-beacon='{\"token\": \"eff2ed428ab3495eb9d4605234f226e8\"}'></script>",
 ]
 
 # ---- page trees (for hreflang parity) ----