fix: production hardening — safety fixes, prediction accuracy, test coverage

Safety:
- Async input handler: await all handleInput() calls, prevents unhandled rejections
- Fix emergencyStop case mismatch: "emergencyStop" → "emergencystop" matching config
- Implement showCoG() method (was routing to undefined)
- Null guards on 6 methods for missing curve data
- Editor menu polling timeout (5s max)
- Listener cleanup on node close (child measurements + state emitter)
- Tick loop race condition: track startup timeout, clear on close

Prediction accuracy:
- Remove efficiency rounding that destroyed signal in canonical units
- Fix calcEfficiency variant: hydraulic power reads from correct variant
- Guard efficiency calculations against negative/zero values
- Division-by-zero protection in calcRelativeDistanceFromPeak
- Curve data anomaly detection (cross-pressure median-y ratio check)
- calcEfficiencyCurve O(n²) → O(n) with running min
- updateCurve bootstraps predictors when they were null

Tests: 43 new tests (76 total) covering emergency stop, shutdown/maintenance
sequences, efficiency/CoG, movement lifecycle, output format, null guards,
and listener cleanup.

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

rotatingMachine.html

@@ -67,11 +67,15 @@
 
     oneditprepare: function() {
       // wait for the menu scripts to load
+      let menuRetries = 0;
+      const maxMenuRetries = 100; // 5 seconds at 50ms intervals
       const waitForMenuData = () => {
         if (window.EVOLV?.nodes?.rotatingMachine?.initEditor) {
           window.EVOLV.nodes.rotatingMachine.initEditor(this);
-        } else {
+        } else if (++menuRetries < maxMenuRetries) {
           setTimeout(waitForMenuData, 50);
+        } else {
+          console.warn("rotatingMachine: menu scripts failed to load within 5 seconds");
         }
       };
       waitForMenuData();