Serve missing *.thumbnail.png requests when the SVG sidecar exists, and schedule async PNG rasterization after public HTML is materialized so WeChat og:image URLs stop 404ing.
Co-authored-by: Cursor <cursoragent@cursor.com>
Track application source and tests; exclude local env, user workspaces, and runtime data via .gitignore.
Co-authored-by: Cursor <cursoragent@cursor.com>