feat: remove ai-chat extension from hosted version, move chat widget to bottom-right

Remove ai-chat from extensions.config.json and docker/extensions.hosted.json
(kept in self-hosted config). Remove ChatWidget imports from dashboard layout
and root page. Reposition chat widget FAB and panel to bottom-right corner.
Regenerate extension registry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/(dashboard)/layout.tsx

@@ -1,7 +1,6 @@
 import { createClient } from '@/lib/supabase/server'
 import { redirect } from 'next/navigation'
 import DashboardNav from '@/components/dashboard/DashboardNav'
-import { ChatWidget } from '@/components/chat'
 import { RecaptIdentify } from '@/components/RecaptIdentify'
 import type { EntityType } from '@/types'
 
@@ -55,7 +54,6 @@ export default async function DashboardLayout({
           {children}
         </div>
       </main>
-      <ChatWidget />
       <RecaptIdentify
         userId={user.id}
         email={user.email}