final: complete airtight hardening (strict constraints, numerical stability, performance metrics)

security: patch 5 critical grader and environment vulnerabilities

self push after fixing few errors

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

Fix: Clamp score strictly between 0.01 and 0.99 for validator

Initial Submission: SQL Schema Migration Agent for OpenEnv Hackathon