fix: realistic sinus + continuous pump control + dead zone elimination

Sinus inflow: 54-270 m³/h (base 0.015 + amplitude 0.06 m³/s), 4 min
period. Peak needs 1-2 pumps, never all 3 = realistic headroom.

PS control: continuous proportional demand when level > stopLevel, not
just when > startLevel && filling. Pumps now ramp down smoothly as
basin drains toward stopLevel instead of staying stuck at last setpoint.

pumpingStation e8dd657: dead zone elimination
build_flow.py: sinus tuned for gradual pump scaling visibility

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

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

@@ -1239,9 +1239,16 @@ def build_drivers_tab():
     nodes.append(function_node(
         "sinus_fn", TAB_DRIVERS, LANE_X[1] + 220, y + 40,
         "sinus inflow (m³/s)",
-        "const base = 0.02;        // m³/s  (~72 m³/h always)\n"
-        "const amplitude = 0.10;   // m³/s  (~360 m³/h peak)\n"
-        "const period = 120;       // seconds per full cycle\n"
+        "// Realistic wastewater inflow profile:\n"
+        "//   base      = minimum dry-weather flow (always present)\n"
+        "//   amplitude = peak wet-weather swing on top of base\n"
+        "//   range     = base → base+amplitude = 54 → 270 m³/h\n"
+        "//   1 pump handles up to ~223 m³/h, so peak needs 2 pumps.\n"
+        "//   3 pumps (669 m³/h) are never needed = realistic headroom.\n"
+        "//   period    = 240s (4 min) — slow enough to see pump ramp on dash.\n"
+        "const base = 0.015;       // m³/s  (~54 m³/h dry weather)\n"
+        "const amplitude = 0.06;   // m³/s  (~216 m³/h peak swing)\n"
+        "const period = 240;       // seconds per full cycle\n"
         "const t = Date.now() / 1000; // seconds since epoch\n"
         "const q = base + amplitude * (1 + Math.sin(2 * Math.PI * t / period)) / 2;\n"
         "return { topic: 'q_in', payload: q, unit: 'm3/s', timestamp: Date.now() };",