Add Reuse Before You Write and Necessary Code Only sections to AGENTS.md,
promote quality probes into a dedicated seventh adversarial-validation
role (simplicity adversary), extend rust-code-quality checks, and dedupe
code-change-verification's restated Rust checklist into a pointer.
Add a default-on multi-role adversarial validation policy to the root
AGENTS.md (risk tiers, six reviewer roles, findings protocol, exit
criteria), a shared adversarial-validation skill with repo-specific
attack probes grounded in shipped bugs, seven audit fixes to the root
instruction files, and an actionlint gate for workflow changes.