fix: stopLevel hysteresis works — bump rotatingMachine + MGC

Pump-shutdown deadlock fix split across two submodules:

- rotatingMachine@8f9150e: shutdown sequence clears state.delayedMove
  so the abort-and-return-to-operational path doesn't auto-pickup the
  queued setpoint and re-engage the pump.
- machineGroupControl@ea2857f: turnOffAllMachines clears MGC's
  _delayedCall and serializes per-pump shutdown so PS's 2 s tick loop
  can't interrupt an in-flight shutdown.

Live verification on pumpingstation-complete-example demo: basin now
shuts pumps off at stopLevel cleanly, reverses to fill, completes the
hysteresis cycle.

Also disable the trends page in the demo flow (build_flow.py + regen
flow.json). FlowFuse ui-chart's per-series server-side history buffer
(7 charts × ~20 series × 3600-point retention) was saturating the
Node-RED event loop at 129% CPU, making the dashboard freeze on every
click. Trends remain available — just disabled by default; flip the
ui_page_trends "d" key to false to re-enable.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

examples/pumpingstation-complete-example/build_flow.py

@@ -211,6 +211,7 @@ def dashboard_scaffold():
         "layout": "grid", "theme": "ui_theme",
         "breakpoints": [{"name": "Default", "px": "0", "cols": "12"}],
         "order": 2, "className": "",
+        "d": True,
     }
     return [base, theme, page_realtime, page_trends]