feat: add AgentEvaluator class

This class will evaluate Agent' results and report to user

src/crewai/evaluation/json_parser.py

@@ -0,0 +1,30 @@
+"""Robust JSON parsing utilities for evaluation responses."""
+
+import json
+import re
+from typing import Dict, Any
+
+
+def extract_json_from_llm_response(text: str) -> Dict[str, Any]:
+    try:
+        return json.loads(text)
+    except json.JSONDecodeError:
+        pass
+
+    json_patterns = [
+        # Standard markdown code blocks with json
+        r'```json\s*([\s\S]*?)\s*```',
+        # Code blocks without language specifier
+        r'```\s*([\s\S]*?)\s*```',
+        # Inline code with JSON
+        r'`([{\\[].*[}\]])`',
+    ]
+
+    for pattern in json_patterns:
+        matches = re.findall(pattern, text, re.IGNORECASE | re.DOTALL)
+        for match in matches:
+            try:
+                return json.loads(match.strip())
+            except json.JSONDecodeError:
+                continue
+    return text