Fix Amplify environment variable configuration

- Add amplify.yml for proper build configuration
- Update next.config.ts to expose YOUTUBE_API_KEY env var
- This should fix the issue with secrets not being available in production

🤖 Generated with [Claude Code](https://claude.ai/code)

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

amplify.yml

@@ -0,0 +1,20 @@
+version: 1
+frontend:
+  phases:
+    preBuild:
+      commands:
+        - npm ci
+    build:
+      commands:
+        - env | grep YOUTUBE_API_KEY || echo "YOUTUBE_API_KEY not found in environment"
+        - npm run build
+  artifacts:
+    baseDirectory: .next
+    files:
+      - '**/*'
+  cache:
+    paths:
+      - node_modules/**/*
+      - .next/cache/**/*
+  buildPath: /
+appRoot: /