- Replaced local `SecurityConfig` in `ping-service` with the shared `infrastructure:security` module.
- Added `GlobalSecurityConfig` to standardize OAuth2, JWT validation, and CORS for all services.
- Introduced new endpoints (`/ping/public`, `/ping/secure`) with role-based access control.
- Updated database schema with Flyway migration (`V1__init_ping.sql`) and refactored persistence layer to align with the standardized approach (`createdAt` field).
- Enhanced application configuration (`application.yaml`) to use shared security and Flyway settings.