fix: safety overfill keeps pumps running + minHeightBasedOn=inlet

pumpingStation 5e2ebe4: overfill safety no longer shuts down machine
groups or blocks level control. Pumps keep running during overfill
(sewer can't stop receiving). Only upstream equipment is shut down.

Demo config: minHeightBasedOn=inlet (not outlet). The minimum height
reference for the basin is the inlet pipe elevation — sewage flows
in by gravity and the basin level can't go below the inlet without
the sewer backing up.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/pumpingstation-3pumps-dashboard/build_flow.py

@@ -598,7 +598,7 @@ def build_process_tab():
         "maxFlowLevel": 3.5,     # 100% pump demand at this level
         # Hydraulics
         "refHeight": "NAP",
-        "minHeightBasedOn": "outlet",
+        "minHeightBasedOn": "inlet",
         "basinBottomRef": 0,
         "staticHead": 12,
         "maxDischargeHead": 24,

examples/pumpingstation-3pumps-dashboard/flow.json

@@ -865,7 +865,7 @@
     "minFlowLevel": 2.0,
     "maxFlowLevel": 3.5,
     "refHeight": "NAP",
-    "minHeightBasedOn": "outlet",
+    "minHeightBasedOn": "inlet",
     "basinBottomRef": 0,
     "staticHead": 12,
     "maxDischargeHead": 24,