Add Codex Reliability Gap Map #01

[yangfei222666-9]

Summary

• Add Codex Reliability Gap Map [codex] add 30s HUD demo script #1 as a clean-scope research proof.
• Include a deterministic 30-issue public GitHub issue sample with explicit cannot_claim boundaries.
• Add a validator and tests that keep the research table, JSON sample, failure-mode mapping, and limitations aligned.

Validation

• python3 scripts/check_codex_gap_map.py
• ~/.venvs/taiji-py312/bin/python -m pytest tests/test_codex_gap_map.py -q

Scope Boundaries

• This PR intentionally contains only the Gap Map research files.
• This is a scoped review of public user reports, not a prevalence study.
• Open issues are treated as reported symptoms, not confirmed product defects.
• Provider/model output is not used as canonical truth.

Related

• Clean-scope replacement for PR Add Codex Reliability Gap Map #01 #42; PR Add Codex Reliability Gap Map #01 #42 was not modified or deleted.