IAV-255/feat: Implement Agent Language Configuration Management

Overview

This MR introduces language configuration management for customer care agents, allowing dynamic control over supported languages and automatic language detection.

Changes

New Features

• GET /{agentUid}/language-config - Retrieve agent language configuration
• PUT /{agentUid}/language-config - Update agent language settings

Core Functionality

1. Auto Language Detection Mode

   • Toggle automatic language detection on/off
   • When enabled, no language configuration required

2. Manual Language Configuration

   • Configure multiple supported languages
   • Set one language as default
   • Automatic ISO code normalization to lowercase

Validation Rules

• Minimum one language required when auto-detection disabled
• Default language ISO code must exist in languages list
• No duplicate ISO codes allowed (case-insensitive)
• No duplicate language names allowed (case-insensitive)
• Default language ISO code required when auto-detection disabled

Technical Details

• DTOs implemented with Swagger documentation
• Comprehensive validation using Jakarta Validation
• Transaction management for data consistency
• Detailed logging for audit trail
• Proper error handling with FunctionalException

Closes IAV-255