Added `/ping/sync` endpoint with timestamp-based Delta-Sync functionality to efficiently support offline-first clients. Extended `PingApi` and frontend clients (`PingApiClient`, `PingApiKoinClient`) with `syncPings`. Updated repository, service, and controller logic for sync handling, including new JPA query `findByCreatedAtAfter`. Adjusted test doubles and completed unit tests for backend and frontend alignment. Documented sync approach and API usage.
- 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.
stefan