feat: Add core and agent family package structure

📋 Overview

This MR introduces the foundational core packages and reorganizes agent-related entities into a family-based package structure to support multi-family agent microservices architecture.

🎯 Motivation

• Establish consistent base classes for all entities and DTOs across the project
• Organize agent entities by family to enable independent microservice development
• Prepare infrastructure for multiple agent families (customerCare, legal, accounting, etc.)
• Eliminate circular dependencies between agent family packages

📦 What's Added

Core Packages

• core.entities: BaseEntity with auto-generated ID, UUID, and timestamps
• core.dtos: BaseEntityDTO with common DTO fields
• core.enumerations: Placeholder for future core enumerations

Agent Common Packages

• agent.common.entities: Shared entities used across all agent families
  • Agent, AgentLanguage, ConversationSession, KnowledgeDocument, AgentMessage, AgentPromptTemplate
• agent.common.enumerations: Shared enumerations
  • AgentFamily, AgentType, ResponseStyle, ToneVoice, MessageChannel, SessionStatus, MessageDirection

Agent CustomerCare Packages

• agent.customerCare.entities: Customer care specific entities
  • AgentWorkingHours, DailySchedule, Client, Ticket
• agent.customerCare.enumerations: Customer care specific enumerations
  • DayOfWeek, TicketChannel, TicketPriority, TicketStatus

Future Agent Families (Placeholders)

• agent.accounting
• agent.community
• agent.legal
• agent.personal
• agent.seo

🏗️ Architecture Benefits

• Modularity: Each agent family can be developed independently
• Microservice-ready: Each microservice scans only core + agent.common + its specific family package
• No circular dependencies: Clean dependency graph (family packages → common → core)
• Scalability: Easy to add new agent families without impacting existing ones
• Consistency: All entities inherit from BaseEntity for standardized persistence

🔍 Technical Details

• All entities extend BaseEntity for consistent ID and timestamp management
• BaseEntity includes UUID field for external API references
• Automatic timestamp management with @CreationTimestamp and @UpdateTimestamp
• BaseEntityDTO uses @SuperBuilder for proper DTO inheritance support

✅ Checklist

• Core packages created with BaseEntity and BaseEntityDTO
• Agent common packages with shared entities and enums
• Agent customerCare packages with family-specific components
• Placeholder packages for future agent families
• Zero circular dependencies verified
• All entities properly extend BaseEntity
• Changelog updated

📝 Notes

The core packages are designed to be reusable across all modules (agent and non-agent).