docs(review-skill): ban hardcoded message checks and include symbol-binding signals

Author: lmeyerov

agents/skills/review/SKILL.md

@@ -161,7 +161,7 @@ git show origin/<base>:<file>
 
 - Test coverage should mirror changed areas in `graphistry/tests/**`.
 - Prefer behavioral tests over implementation-detail assertions.
-- Control-flow checks (runtime code, tests, and prompt-routing logic) must use structured signals (for example `code` and context keys like `field`/`value`) and never message-substring matching.
+- Control-flow checks (runtime code, tests, and prompt-routing logic) must use structured signals (for example `code`, context keys like `field`/`value`, AST/symbol kinds, and stable symbol-binding metadata/files) and never **hardcoded** message-substring matching.
 - Run focused validation before escalating severity when feasible:
 
 ```bash