feat(pre-push-safety-net): establish shared push and engine contracts

.kiro/specs/pre-push-safety-net/research.md

@@ -6,7 +6,9 @@
 - User direction: a scalable pre-push safety net as AI accelerates development; WordPress is one case.
 - Clarifications: advisory must be actionable, not SAST noise; the ranker is the scope mechanism;
   third-party vendor code must remain outside targets and graphs.
-- Requirements and design are proposals, not approved or implemented. No hook latency claim is made.
+- Requirements, design and tasks are now approved, and group 1 implementation is verified complete; see
+  `tasks.md` for verified completion. The discovery log below preserves the earlier drafting state
+  and measurements. No hook latency claim is made.
 
 ## Research Log