Add telemetry counter for Redis pub/sub reconnection attempts

### 🔖 Enhancement description Add a telemetry counter telemetry.pubsubReconnectionCounter in app/realtime.php to track Redis pub/sub connection reconnection attempts. The counter will be incremented in the catch block that handles pub/sub connection errors (around line 616). ### 🎤 Pitch Realtime functionality depends entirely on Redis pub/sub for message distribution. When pub/sub connections fail, the system automatically retries, but there's currently no metric to monitor the frequency or pattern of these reconnections. This enhancement provides: - Infrastructure visibility: Operators can detect Redis instability before it impacts users - Alerting capability: Spikes in reconnection attempts can trigger infrastructure alerts - Low overhead: Single counter increment per failed connection attempt - Consistent pattern: Follows existing telemetry patterns already in the file (lines 398-400 show telemetry.connectionCounter, telemetry.connectionCreatedCounter, and telemetry.messageSentCounter) Implementation follows existing patterns: The file already uses this telemetry pattern: 1. Registration (around line 400): ``` php $register->set('telemetry.connectionCounter', fn () => $telemetry->createUpDownCounter('realtime.server.open_connections')); $register->set('telemetry.connectionCreatedCounter', fn () => $telemetry->createCounter('realtime.server.connection.created')); $register->set('telemetry.messageSentCounter', fn () => $telemetry->createCounter('realtime.server.message.sent')); ``` Usage throughout the file: ``` php $register->get('telemetry.connectionCounter')->add(1); $register->get('telemetry.connectionCreatedCounter')->add(1); $register->get('telemetry.messageSentCounter')->add($total); The proposed change follows this exact pattern: ``` - Register the counter in onWorkerStart: $register->set('telemetry.pubsubReconnectionCounter', fn () => $telemetry->createCounter('realtime.server.pubsub.reconnection')); - Increment it in the catch block: $register->get('tel…