feat: implement chatbot logic and notification system with security updates

Overview

This Merge Request implements the core logic for the AI-powered chatbot and the notification system within the Support microservice. It also includes critical security configurations to allow public access to the chatbot and ensures session resilience.

Key Changes

Chatbot & AI Integration

• Integrated OpenAI API to provide intelligent support responses.
• Implemented ChatbotService and ChatbotController to handle user interactions.
• Added Session Resilience: Implemented automatic session recovery to prevent 404 errors during long-running or expired chatbot sessions.

Notification System

• Created the foundation for the notification module (Services, Repositories, and Controllers).
• Added support for templates and user preferences.

🔒 Security & Configuration

• Updated SecurityConfig to permit public access to chatbot endpoints (no authentication required for basic assistance).
• Externalized sensitive data (API Keys) using environment variables.
• Configured CORS and header filtering to ensure smooth communication with the frontend gateway.

Architecture & Refactoring

• Cleaned up exception handling with a GlobalExceptionHandler.
• Added unit tests for AgentService and NotificationService to ensure reliability.

Testing Performed

• Validated all endpoints via Postman.
• Verified that the chatbot is accessible without a Keycloak token while other support endpoints remain secured.
• Ran mvn clean install to ensure no regressions in the build.