refactor: Implement CrewAI Flow for email processing

- Add EmailState model for Flow state management
- Create EmailProcessingFlow class with event-based automation
- Update tools and crews for Flow integration
- Add comprehensive Flow tests
- Implement error handling and state tracking
- Add mock implementations for testing

This implementation uses CrewAI Flow features to create an event-based
email processing system that can analyze emails, research senders,
and generate appropriate responses using specialized AI crews.

Co-Authored-By: Joe Moura <joao@crewai.com>

tests/test_response_crew.py

@@ -0,0 +1,45 @@
+"""Test script for response crew functionality"""
+from response_crew import ResponseCrew
+from email_analysis_crew import EmailAnalysisCrew
+import json
+
+def test_response_crew():
+    """Test the response crew functionality"""
+    try:
+        # First get analysis results
+        analysis_crew = EmailAnalysisCrew()
+        analysis_result = analysis_crew.analyze_email("thread_1")
+
+        if not analysis_result.get("response_needed", False):
+            print("No response needed for this thread")
+            return True
+
+        # Initialize response crew
+        response_crew = ResponseCrew()
+        print("\nTesting response crew...")
+
+        # Draft response
+        result = response_crew.draft_response("thread_1", analysis_result)
+
+        print("\nResponse Results:")
+        print(f"Thread ID: {result['thread_id']}")
+
+        if result.get("error"):
+            print(f"Error: {result['error']}")
+            return False
+
+        print("\nContent Strategy:")
+        print(json.dumps(result['strategy_used'], indent=2))
+
+        print("\nFinal Response:")
+        print(json.dumps(result['response'], indent=2))
+
+        print("\nAll tests completed successfully!")
+        return True
+
+    except Exception as e:
+        print(f"Error during testing: {str(e)}")
+        return False
+
+if __name__ == "__main__":
+    test_response_crew()