fix: market hub WS 1009, user-hub stale reconnect, stats await, Practice live lookup

[TexasCoding]

Summary

v4.1.2 PATCH for live TradingSuite issues #128–#131.

• Market hub close-loops with WS 1009: HUB_RECEIVE_MAX_SIZE=10000 is a byte cap, not a message queue #128 HUB_RECEIVE_MAX_SIZE is pysignalr/websockets incoming frame size in bytes, not a 10,000-message queue. Raise it to the 1 MiB default so MNQ/MES DOM snapshots no longer close-loop with WS 1009.
• Stale-feed watchdog treats 30s of user-hub silence as dead and force-reconnects a healthy suite #129 The stale-feed watchdog no longer treats 30s of user-hub silence as a dead feed (normal while flat). Market-hub freeze detection is unchanged. stop() drops the pysignalr client so reconnect cannot raise Cannot connect while not disconnected. Watchdog-initiated reconnect keeps a single loop.
• Statistics aggregator calls async get_stats() without await (RuntimeWarning on every snapshot) #130 StatisticsAggregator awaits async get_stats() / get_statistics() / get_memory_stats() instead of dropping the coroutine on every snapshot. A timeout no longer falls through to the next method.
• get_instrument(symbol, live=True) raises Instrument not found for TopstepX Practice MNQ/MES #131 get_instrument(symbol, live=True) retries live=False with a warning when Gateway returns a successful empty live/listed search (Practice/sim MNQ/MES). success: false still raises.

Test plan

• tests/realtime/test_async_hub.py — 1 MiB frame cap; stop/start recreates client
• tests/realtime/test_health_monitoring.py — user hub silence is not stale; market freeze still reconnects; watchdog self-stop does not spawn a second loop; reconnect waits for hub run() to finish
• tests/statistics/test_statistics_module.py — async get_stats() is awaited; timeout does not return fallback dict
• tests/client/test_market_data.py — live=True empty list falls back; live=False still raises; success=false does not fallback
• uv run pytest tests/ --ignore=tests/benchmarks/ (3175 passed before review follow-ups; targeted suites green after)
• uv run ruff check src/ and .venv/bin/python -m mypy src/

Fixes #128
Fixes #129
Fixes #130
Fixes #131