feat: add asset preferences, video research, and Remotion ad assets

- Add thumbs-down feedback modal and preference API endpoint
- Add AI UGC video platforms research doc
- Add ReflectAd Remotion composition with public flow assets
- Add gemini-ad-designer and poster-ad-designer pipeline skills
- Add research_reflect_v1.1 pipeline script

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/auth.ts

@@ -28,4 +28,5 @@ export const { handlers, signIn, signOut, auth } = NextAuth({
     signIn: "/login",
   },
   secret: process.env.NEXTAUTH_SECRET,
+  trustHost: true,
 });