av: clone broadcastbeat sources + AV Beat rebrand (Phase 1)

- Replaces the prior Rocket scaffold (saved on pre-bb-clone-rollback branch)
- Domain: broadcastbeat.com -> avbeat.com
- Brand: Broadcast Beat -> AV Beat
- Slug: broadcastbeat -> avbeat (package, identifiers)
- Schema fallback: bb -> av (env var name unchanged)
- Placeholder AV BEAT logo (gold->red gradient) at /assets/logos/av.svg
- All BB/RMP logo references repointed

Outstanding before public DNS swap:
  - Supabase av schema bootstrap (mirror of bb tables)
  - WordPress archive import (avbeat-com -> av.articles)
  - Coolify env vars
  - dev-avbeat.onsethost.com staging deploy + visual review

src/lib/supabase/client.tsx

@@ -5,7 +5,7 @@ export function createClient() {
     process.env.NEXT_PUBLIC_SUPABASE_URL!,
     process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
     {
-      db: { schema: process.env.NEXT_PUBLIC_SUPABASE_SCHEMA || 'avb' },
+      db: { schema: process.env.NEXT_PUBLIC_SUPABASE_SCHEMA || 'bb' },
       cookies: {
         getAll() {
           if (typeof document === 'undefined') return [];