[codex] Add read-only doctor snapshot

[na-navi]

Summary

• add --doctor mode to emit a read-only JSON health snapshot before Hermes/model-cache work
• report runtime, dependency, plugin, environment, and fixed .codex observations with path redaction
• redact HOME/USERPROFILE paths to ~ and other absolute paths to basename-only <absolute-path>/... form
• document doctor mode in Japanese, English, and Chinese READMEs plus skill docs

Safety boundaries

• no Hermes execution
• no model cache write
• no workspace write probe
• no config/auth/session content reads
• no recursive .codex scan

Verification

• python -m unittest scripts.test_invoke_cormes (20 tests)
• python scripts\validate-plugin.py
• git diff --check
• installed-plugin smoke: python %USERPROFILE%\.codex\plugins\cormes\scripts\invoke-cormes.py --doctor

Closes #25