Archived obsolete Ping-Service documentation (`ping-service.md`, `PingService.md`) and replaced them with updated references (`PingService_Reference.md`, `Testing_with_Postman.md`). Improved clarity and organization of backend guides with a focus on current architecture, testing approaches, and microservice design principles. Documented the transition with a session log for traceability.
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.
Implemented a standardized folder structure for domain documentation to improve clarity and maintainability. Migrated existing files to the new structure, updated links in related documentation, and added README files for navigation and guidance.
