[codex] add Judge QA schema and fixtures

[greenthree]

Summary

• add judge.qa.schema_version: 1 parsing and stable lint diagnostics for Checker and Interactor QA cases
• resolve and hash problem-local fixtures with Windows case-insensitive collision checks and fixed resource limits
• track judge-fixtures/ and code/judge-qa/ through source hashes and checkpoints without publishing them into PDFs, packages, metadata, or Manifests
• add independent checker-qa and interactor-qa Schema v1 workspaces plus regression coverage

Scope

This is the ROADMAP 2.1 P0 slice only. It does not execute fixtures or add the judge-qa CLI, evidence, seal/report gates, WebUI support, or Legacy support.

Validation

• npm run check: 598 passed, 30 skipped
• npm run pack:check: 216/5 files
• Python py_compile
• Skill validation
• git diff --check
• current Core against phtest: nine-problem lint passed
• phtest L02 judge --no-cache: 33 inputs, 3 solutions, 99 case runs, all_expectations_met