Description

Implements Microservices-aware Offline Capabilities for the TeachLink frontend to improve the user experience under flaky network conditions. This introduces the OfflineSyncManager utility which caches mutations (POST, PUT, DELETE) locally when the network drops and intelligently routes them to the correct backend microservice (Auth, Courses, Groups, etc.) when connectivity is restored.

Changes

• ✅ Created src/lib/offline/OfflineSyncManager.ts to handle offline queuing and routing.
• ✅ Added comprehensive unit tests in src/lib/offline/__tests__/OfflineSyncManager.test.ts.
• ✅ Created OFFLINE_MICROSERVICES_SUMMARY.md with architectural documentation and integration instructions.

Features

• Microservice Routing: Routes queued requests to specific domain APIs.
• Durable Queue: LocalStorage-backed request queuing ensures data survives browser refreshes.
• Chronological Processing: Requests are processed in the order they were generated when connectivity returns.
• Graceful Degradation: Maintains data integrity by halting the queue if a microservice endpoint errors upon reconnection.

Testing

• Unit tests written mocking localStorage, navigator.onLine, and fetch.
• Verified offline enqueuing behavior.
• Verified correct microservice URL resolution upon online synchronization.
• Status: 100% tests passing ✅

Checklist

• Code follows project coding standards
• All tests pass
• No regression in existing functionality
• Documentation is complete
• Performance impact is minimal

Related Issues

Closes #373