feat(api-graphql): add WebSocket health monitoring and manual reconnection

[anivar]

This PR addresses several long-standing user requests for better WebSocket connection control in the GraphQL API client. Users have reported issues with WebSocket connections not automatically reconnecting after network interruptions and lacking visibility into connection health status ( Fixes #9749, #4459, #5403, #7057).

The implementation enhances the existing AWSWebSocketProvider class with four new methods that leverage the existing ConnectionStateMonitor infrastructure and keep-alive tracking. These methods provide both real-time health monitoring and manual connection control that users have been requesting.

Enhanced WebSocket Provider Methods

• getConnectionHealth() - Returns current health state using in-memory keep-alive tracking
• getPersistentConnectionHealth() - Returns health state with cross-session persistence via AsyncStorage/localStorage
• isConnected() - Checks if WebSocket.readyState === OPEN for immediate connection status
• reconnect()/disconnect() - Manual connection control for user-triggered reconnection scenarios

Technical Implementation

The health monitoring uses the existing 65-second keep-alive threshold (DEFAULT_KEEP_ALIVE_ALERT_TIMEOUT) already established in the AppSync WebSocket protocol. A WebSocket is considered healthy when three conditions are met: connection state is Connected, a keep-alive was received within 65 seconds, and the underlying WebSocket readyState is OPEN.

For persistence, the implementation uses a platform-safe approach with AsyncStorage for React Native and localStorage fallback for web platforms. Keep-alive timestamps are stored at 'AWS_AMPLIFY_LAST_KEEP_ALIVE' to avoid key collisions. When storage is unavailable, the feature gracefully degrades to in-memory tracking only.

All changes are backward compatible with no breaking changes to existing functionality.

[bobbor]

Thanks for opening the PR.
Please take a look at the comments