fix(marketing): strip dead Discord invite from footer; docs: Scout tier -> sonnet[1m]

discord.gg/corrosion is an Unknown Invite (verified via Discord API) -
no dead community promises on the marketing site. Re-add when a real
server exists. Discord *webhook* feature copy stays; that's shipped.

AGENTS.md Scout tier haiku -> sonnet[1m] confirmed by Commander:
marginal price difference, 1m context window pays for itself on recon.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/components/layout/MarketingLayout.vue

@@ -62,7 +62,6 @@ const panelUrl = import.meta.env.VITE_PANEL_URL ?? ''
           <div class="footer__col">
             <h5>Support</h5>
             <RouterLink :to="{ name: 'faq' }">FAQ</RouterLink>
-            <a href="https://discord.gg/corrosion" target="_blank" rel="noopener">Discord</a>
             <RouterLink to="/status">Status</RouterLink>
           </div>
           <div class="footer__col">