Update workflow model profiles for GPT-6

[xeonvs]

Changes

• Route deterministic commands and test execution through tools, use GPT-6 Luna for bounded utility semantics and GPT-6 Sol for ordinary exploration, implementation, and review.
• Keep GPT-6 Astra for explicit user choice or confirmed high-consequence escalation; retain GPT-5.6 Terra as an availability/evaluation fallback.
• Upgrade exact pristine Codex agent templates in previously opted-in target repositories while preserving customized files and model pins.
• Release engineering-workflow 0.9.8 with byte-identical Codex/Claude packages.

Validation

• scripts/dev_check.py release: 12/12 passed, 266 tests (one skipped), privacy and Gitleaks clean.
• Codex plugin validator, source and packaged skill quick validation, strict Claude plugin/marketplace validation, and Claude tag dry-run passed.