Implement two new database functions: get_top_authors aggregates star counts across posts, projects, and gists tables with 60-second TTL caching, and get_user_stars computes total stars for a given user_uid. Refactor feed page to use get_top_authors instead of raw users table query, and display aggregated star count on profile pages via get_user_stars. Add Playwright integration test verifying profile star count increments after a post vote.