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_email_tool.py

@@ -0,0 +1,48 @@
+"""Test script for email processing tool"""
+from gmail_tool import EmailTool
+from datetime import datetime, timedelta
+
+def test_email_tool():
+    """Test email processing tool functionality"""
+    try:
+        # Initialize tool
+        email_tool = EmailTool()
+
+        # Test getting email thread
+        print("\nTesting thread retrieval...")
+        thread = email_tool.get_email_thread("thread_1")
+        print(f"Retrieved thread: {thread.subject}")
+        print(f"Participants: {', '.join(thread.participants)}")
+        print(f"Messages: {len(thread.messages)}")
+
+        # Test finding similar threads
+        print("\nTesting similar thread search...")
+        similar = email_tool.find_similar_threads("meeting")
+        print(f"Found {len(similar)} similar threads")
+        for t in similar:
+            print(f"- {t.subject}")
+
+        # Test sender history
+        print("\nTesting sender history...")
+        history = email_tool.get_sender_history("john@example.com")
+        print(f"Sender: {history['name']} from {history['company']}")
+        print(f"Last interaction: {history['last_interaction']}")
+        print(f"Interaction frequency: {history['interaction_frequency']}")
+
+        # Test thread context analysis
+        print("\nTesting thread context analysis...")
+        context = email_tool.analyze_thread_context("thread_1")
+        print("Context Summary:")
+        print(f"Thread length: {context['context_summary']['thread_length']} messages")
+        print(f"Time span: {context['context_summary']['time_span']} days")
+        print(f"Relationship: {context['context_summary']['sender_relationship']}")
+
+        print("\nAll tests completed successfully!")
+        return True
+
+    except Exception as e:
+        print(f"Error during testing: {str(e)}")
+        return False
+
+if __name__ == "__main__":
+    test_email_tool()