Improve WebSocket reconnection with exponential backoff and developer visible connection state events

### 🔖 Enhancement description Add proper exponential backoff with jitter to WebSocket reconnection logic in frontend SDKs, and provide optional callback events for connection state changes (connected, disconnected, reconnecting, reconnection-failed) to give developers visibility into real-time connection status. ### 🎤 Pitch Current implementation uses step-based backoff (1s → 5s → 10s → 60s) instead of industry-standard exponential backoff, and only logs reconnection attempts to console without developer-visible events. This makes it difficult to: - Show "Reconnecting..." UI to users during network issues - Implement custom error handling or fallback logic - Monitor connection health in production applications - Follow WebSocket best practices for production resilience - Industry standard is Math.min(base * 2^attempt + jitter, max) which provides smoother backoff and reduces server load - during outages. Adding optional callbacks (e.g., onConnect, onDisconnect, onReconnecting, onReconnectFailed) would align - - Appwrite with Firebase Realtime Database, Supabase, and Socket.io patterns. Example usage: ``` typescript client.subscribe('documents', (payload) => { /* ... */ }, { onConnect: () => console.log('Connected'), onDisconnect: () => showReconnectingUI(), onReconnecting: (attempt) => updateRetryCount(attempt), onReconnectFailed: () => showOfflineMode() }); ``` Files to Modify (3 files, identical changes) - public/sdk-web/client.ts - public/sdk-console/client.ts - public/sdk-project/client.ts ### 👀 Have you spent some time to check if this issue has been raised before? - [x] I checked and didn't find similar issue ### 🏢 Have you read the Code of Conduct? - [x] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)