Fixed heap out of memory on network issues

[aizo231]

Heap out of memory error happened, because WebSocket instance was not terminated when establishing new one, leading to massive spike in memory on network errors.

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Note

Medium Risk
Changes WebSocket lifecycle/reconnect behavior by terminating and nulling sockets on error/close, which could affect reconnect timing and any downstream assumptions about ws being non-null.

Overview
Improves RealTimeDataClient resilience to network failures by explicitly cleaning up WebSocket instances on error and close (remove listeners, terminate(), and clear ws) before attempting auto-reconnect, preventing buildup of orphaned sockets and memory growth.

Adds guards so ping() and the pong-driven ping loop only run when a socket exists, and ensures DISCONNECTED status is emitted on errors as well as closes.

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