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/app/admin/newsletter/campaign-editor/page.tsx

@@ -632,7 +632,7 @@ export default function CampaignEditorPage() {
                   </div>
                   <div className="flex-1 min-w-0">
                     <div className="flex items-center gap-2">
-                      <span className="text-xs font-medium text-white">Broadcast Beat</span>
+                      <span className="text-xs font-medium text-white">AV Beat</span>
                       <span className="text-[10px] text-[#444]">now</span>
                     </div>
                     <p className="text-xs text-[#888] truncate">{campaign.subject || 'Your subject line…'}</p>
@@ -645,7 +645,7 @@ export default function CampaignEditorPage() {
               <div className="p-4 space-y-3 max-h-[400px] overflow-y-auto">
                 {/* Header */}
                 <div className="bg-[#0a0a0a] rounded-lg p-3 text-center border border-[#1a1a1a]">
-                  <p className="text-xs font-bold text-white tracking-widest uppercase">Broadcast Beat</p>
+                  <p className="text-xs font-bold text-white tracking-widest uppercase">AV Beat</p>
                   {campaign.previewText && (
                     <p className="text-[10px] text-[#555] mt-1">{campaign.previewText}</p>
                   )}
@@ -680,7 +680,7 @@ export default function CampaignEditorPage() {
 
                 {/* Footer */}
                 <div className="text-center pt-2 border-t border-[#1a1a1a]">
-                  <p className="text-[9px] text-[#333]">Broadcast Beat · Unsubscribe · View in browser</p>
+                  <p className="text-[9px] text-[#333]">AV Beat · Unsubscribe · View in browser</p>
                 </div>
               </div>
             </div>