feat: implement dynamic ERD visualization, premium dashboard UI, and professional global README

fix: 3 bugs (dead except block, inflated rewards, autocommit conflict) + cleanup

security: patch 5 critical grader and environment vulnerabilities

self push after fixing few errors

feat: expand to 7 tasks (2E/3M/2H) + engine hardening

Initial Submission: SQL Schema Migration Agent for OpenEnv Hackathon