Scale biz_state collects with dedicated workers and non-blocking UI poll.

Add PG claim/NE mutex, persist pool, and biz_state_worker replicas; fix double-SSH and row-count bugs; stop 32m collectNow while-loop from freezing page switches.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/biz_state_worker.py

@@ -0,0 +1,64 @@
+"""Dedicated biz_state collect worker process.
+
+When ``NETX_BIZ_STATE_DEDICATED_WORKERS=true`` (default) and API uses external
+schedulers (``NETX_RUN_INLINE_SCHEDULERS=false``), run one or more replicas:
+
+    python -m netx_api.biz_state_worker
+
+Each process enqueues due tasks, claims queued batches (SKIP LOCKED + NE mutex),
+runs SSH collect → spool, and drains the persist pool. Scale by starting N
+processes on the same host (start_netx.ps1 / .sh do this via replicas).
+"""
+
+from __future__ import annotations
+
+import logging
+import signal
+import time
+
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s %(levelname)s %(name)s: %(message)s",
+)
+_log = logging.getLogger("netx.biz_state.worker")
+
+
+def main() -> None:
+    from .biz_state_scheduler import start_biz_state_scheduler, stop_biz_state_scheduler
+    from .config import settings
+    from .scheduler_heartbeat import start_scheduler_heartbeat_publisher
+
+    stop = False
+
+    def _handle(_sig: int, _frame: object) -> None:
+        nonlocal stop
+        _log.info("shutdown signal received")
+        stop = True
+
+    for sig in (signal.SIGINT, signal.SIGTERM):
+        try:
+            signal.signal(sig, _handle)
+        except Exception:
+            pass
+
+    start_biz_state_scheduler()
+    try:
+        start_scheduler_heartbeat_publisher(role="biz_state_worker")
+    except Exception:
+        _log.exception("biz_state worker heartbeat failed to start")
+
+    _log.info(
+        "biz_state worker started dedicated=%s max_concurrent=%s",
+        bool(getattr(settings, "biz_state_dedicated_workers", True)),
+        int(getattr(settings, "biz_state_max_concurrent_tasks", 16) or 16),
+    )
+
+    while not stop:
+        time.sleep(1.0)
+
+    stop_biz_state_scheduler()
+    _log.info("biz_state worker exiting")
+
+
+if __name__ == "__main__":
+    main()