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>

src/email_processor/email_analysis_crew.py

@@ -0,0 +1,113 @@
+"""
+Email analysis crew implementation using CrewAI.
+Handles comprehensive email analysis including thread history and sender research.
+"""
+from crewai import Agent, Task, Crew, Process
+from typing import Dict, List, Optional
+from datetime import datetime
+
+from .gmail_tool import GmailTool
+
+class EmailAnalysisCrew:
+    """
+    Crew for analyzing emails and determining response strategy.
+    """
+
+    def __init__(self, gmail_tool: Optional[GmailTool] = None):
+        """Initialize analysis crew with required tools"""
+        self.gmail_tool = gmail_tool or GmailTool()
+        self._create_agents()
+
+    def _create_agents(self):
+        """Create specialized agents for email analysis"""
+        self.context_analyzer = Agent(
+            role="Email Context Analyst",
+            name="Context Analyzer",
+            goal="Analyze email context and history",
+            backstory="Expert at understanding email threads and communication patterns",
+            tools=[self.gmail_tool],
+            verbose=True
+        )
+
+        self.research_specialist = Agent(
+            role="Research Specialist",
+            name="Research Expert",
+            goal="Research sender and company background",
+            backstory="Skilled at gathering and analyzing business and personal information",
+            tools=[self.gmail_tool],
+            verbose=True
+        )
+
+        self.response_strategist = Agent(
+            role="Response Strategist",
+            name="Strategy Expert",
+            goal="Determine optimal response approach",
+            backstory="Expert at developing communication strategies",
+            tools=[self.gmail_tool],
+            verbose=True
+        )
+
+    def analyze_email(self,
+                     email: Dict,
+                     thread_history: List[Dict],
+                     sender_info: Dict) -> Dict:
+        """
+        Analyze email with comprehensive context.
+
+        Args:
+            email: Current email data
+            thread_history: Previous thread messages
+            sender_info: Information about the sender
+
+        Returns:
+            Dict: Analysis results including response decision
+        """
+        try:
+            # Create analysis crew
+            crew = Crew(
+                agents=[
+                    self.context_analyzer,
+                    self.research_specialist,
+                    self.response_strategist
+                ],
+                tasks=[
+                    Task(
+                        description="Analyze email context and thread history",
+                        agent=self.context_analyzer
+                    ),
+                    Task(
+                        description="Research sender and company background",
+                        agent=self.research_specialist
+                    ),
+                    Task(
+                        description="Determine response strategy",
+                        agent=self.response_strategist
+                    )
+                ],
+                verbose=True
+            )
+
+            # Execute analysis
+            results = crew.kickoff()
+
+            # Process results
+            return {
+                "email_id": email["id"],
+                "thread_id": email["thread_id"],
+                "response_needed": results[-1].get("response_needed", False),
+                "priority": results[-1].get("priority", "low"),
+                "similar_threads": results[0].get("similar_threads", []),
+                "sender_context": results[1].get("sender_context", {}),
+                "company_info": results[1].get("company_info", {}),
+                "response_strategy": results[-1].get("strategy", {})
+            }
+
+        except Exception as e:
+            print(f"Analysis error: {str(e)}")
+            return {
+                "email_id": email.get("id", "unknown"),
+                "thread_id": email.get("thread_id", "unknown"),
+                "error": f"Analysis failed: {str(e)}",
+                "response_needed": False,
+                "priority": "error"
+            }