Replaces localStorage with a JSON-file backend (server.js). Prayers are
stored in /data/prayers.json, which is mounted as a named Docker volume so
data survives container restarts and rebuilds. React fetches from /api/prayers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DReRqHxSYuVfCzTzQGD9hZ
