Fix skeptic LLM: add User-Agent header to bypass Cloudflare WAF (was getting 403 error code 1010)

Phase 1: Multi-agent extension - REQUEST_REVIEW + REVISE_SECTION + skeptic agent

Add expert scenario - security breach, 4-level difficulty, updated README and openenv.yaml

Fix pre-submission validator - pyproject, uv.lock, main(), openenv-core

final - README + grader fixes + service_match bug fix

Initial deployment — Incident Post-Mortem Writer OpenEnv