fix: address final lint blockers for agent self-evaluation

- Replace U+274C cross-mark examples with ASCII FAIL: prefixes
- Ensure agent-evaluator markdown ends with trailing newline
- Replace markdown placeholder underscores with bracketed placeholders to satisfy markdownlint MD037

agents/agent-evaluator.md

@@ -203,4 +203,4 @@ TOP IMPROVEMENTS:
   3. [Completeness] Handle 429, connection errors, and timeout
 
 VERDICT: Redo with specific fixes. Weakest axis: Accuracy (2/5).
-```
+```