Improve README, tests, and validation script for RL environment

Fix structural phase 2 validation: Clamp all scores rigorously within (0, 1) bounds exclusively

Fix CI validation workflow: Add strict None checks for Mypy compliance

Fix reward calculation logic in SupportTicketEnv to ensure proper accumulation across steps and resolve test failures.

fix: lint/type issues and ensure mypy/ruff pass

chore: prepare Round-1 OpenEnv submission (validator, evaluator, tests, CI, docs)