fix: correct asciinema entrypoint command for server startup

Fixed server endpoints not starting by correcting the entrypoint wrapper
script to use the proper command: /sbin/tini -- /opt/app/bin/server

Changes:
- Updated entrypoint-wrapper.sh to exec /sbin/tini instead of /opt/app/bin/asciinema
- Removed incorrect command: ["start"] from compose.yaml
- Custom CSS injection now working with proper server startup
- Both main (port 4000) and admin (port 4002) endpoints now running

The custom Pivoine theme CSS is successfully injected at container startup
and served via both app.css and hashed app-*.css files.

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

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

asciinema/entrypoint-wrapper.sh

@@ -14,4 +14,4 @@ if [ -f /opt/app/lib/asciinema-1.0.0/priv/static/assets/custom.css ]; then
 fi
 
 # Execute the original entrypoint
-exec /opt/app/bin/asciinema "$@"
+exec /sbin/tini -- /opt/app/bin/server "$@"