Safer mach6 issue assessments
mach6-issue now treats the assessed issue’s own body and comments as the sole source of requirements; linked issues and pull requests are context only unless scope is explicitly re-adopted.- Prior work is classified as adopted, rejected, split, superseded, or unknown, with rejection and split decisions quoted where available.
- Assessments now include an explicit prior-rejections section, preventing rejected or superseded plans from being silently absorbed into requirements, scope, or risks.
- Updated mach6 documentation and regression coverage for the new assessment guardrails.
- Hardened a live OpenRouter overflow test against build-time model-catalog changes while retaining a loud failure when the requested model is unavailable at runtime.
Implemented in PR 524, resolving issue 523.
