Fix remaining broken anchor link in 04-test-repair.md (missed in prior commit)

Author: CSZHK

skills/goal-conditions/examples/04-test-repair.md

@@ -45,7 +45,7 @@ flake repair, demand 5 or 10 — but proof gets harder to read after a few.
   three times each
 - **Mutation testing**: Add proof `npx stryker run --filter auth/session` ≥ N mutation score
   (use this when you suspect tests pass but don't actually verify behavior — pair with
-  [goalkeeper](../references/tools.md#itsuzefgoalkeeper))
+  [goalkeeper](../references/tools.md#itsuzefgoalkeeper--when-the-validator-lies))
 
 ## Common pitfalls when running this