IAV-241/refactor: convert Agent to abstract class with family-specific inheritance

🎯 Objective

Refactor the Agent entity architecture to support multiple agent families through inheritance, improving code organization and type safety.

📋 Changes

Architecture

• Converted Agent from concrete entity to abstract base class
• Implemented JOINED inheritance strategy for agent families
• Created CustomerCareAgent as first family-specific implementation

Entity Changes

Agent (Abstract Base Class)

• Contains fields common to all agent families:
  • displayName, description, family, type
  • ownerUserUid, createdBy, systemPrompt
  • active, knowledgeDocumentsUid
• Maintains common relationships:
  • languages → AgentLanguage
  • conversationSessions → ConversationSession

CustomerCareAgent (Concrete Implementation)

• Extends Agent with customer care specific features:
  • toneVoice, responseStyle, blockedKeywords
• Family-specific relationships:
  • integrations → AgentIntegration
  • faqs → Faq
  • standardInstructions → AgentStandardInstruction
  • customInstructions → AgentCustomInstruction
  • agentWorkingHours → AgentWorkingHours
  • tickets → Ticket
• Hierarchical relationships (parent/sub-agents)

Package Reorganization

• Moved ToneVoice and ResponseStyle enumerations to customerCare.enumerations
• Family-specific entities updated to reference CustomerCareAgent instead of Agent

Database Schema

• New table: customer_care_agents (primary key joins with agents.id)
• Updated foreign key constraints for family-specific relationships
• New collection table: customer_care_agent_blocked_keywords

🎁 Benefits

1. Better Separation of Concerns: Each agent family has its own entity with specific fields
2. Type Safety: Compile-time checking for family-specific relationships
3. Scalability: Easy to add new agent families without polluting base class
4. Cleaner Code: No more null checks for family-specific fields
5. Explicit Relationships: Clear ownership of family-specific entities

⚠️ Breaking Changes

• Agent entity is now abstract and cannot be instantiated directly
• Services and repositories must use family-specific agent classes (e.g., CustomerCareAgent)
• Family-specific entities (Faq, Ticket, etc.) now reference CustomerCareAgent instead of Agent

📚 Related Issues

Closes IAV-241