fix: logic patches for validation schemas, destructive query penalties, and metadata payload generation

fix: full audit pass — timer, DML timeout, sqlite_sequence, env_lock, done indicator, dockerignore, schema hints, shutdown hook

fix: stateful agent, DDL clean slate grader, Llama-3 default, hint clarity

core: integrated universal SQLite hashing grader, intent mechanics, and dense logic rewards

Initialize OpenEnv SQL Environment