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>

test/integration/movement-lifecycle.integration.test.js

@@ -0,0 +1,75 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const Machine = require('../../src/specificClass');
+const { makeMachineConfig, makeStateConfig } = require('../helpers/factories');
+
+test('movement from 0 to 50% updates position and predictions', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  assert.equal(machine.state.getCurrentState(), 'operational');
+
+  machine.updateMeasuredPressure(1000, 'downstream', { timestamp: Date.now(), unit: 'mbar', childName: 'pt' });
+
+  await machine.handleInput('parent', 'execMovement', 50);
+
+  const pos = machine.state.getCurrentPosition();
+  const { min, max } = machine._resolveSetpointBounds();
+  // Position should be constrained to bounds
+  assert.ok(pos >= min && pos <= max, `Position ${pos} should be within [${min}, ${max}]`);
+
+  const flow = machine.measurements.type('flow').variant('predicted').position('downstream').getCurrentValue();
+  assert.ok(flow > 0, 'Predicted flow should be positive at non-zero position');
+});
+
+test('flowmovement sets position based on flow setpoint', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  machine.updateMeasuredPressure(1000, 'downstream', { timestamp: Date.now(), unit: 'mbar', childName: 'pt' });
+
+  // Request 100 m3/h flow — the machine should calculate the control position
+  await machine.handleInput('parent', 'flowMovement', 100);
+
+  const pos = machine.state.getCurrentPosition();
+  assert.ok(pos > 0, 'Position should be non-zero for a non-zero flow setpoint');
+});
+
+test('sequential movements update position correctly', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  machine.updateMeasuredPressure(1000, 'downstream', { timestamp: Date.now(), unit: 'mbar', childName: 'pt' });
+
+  await machine.handleInput('parent', 'execMovement', 30);
+  const pos30 = machine.state.getCurrentPosition();
+
+  await machine.handleInput('parent', 'execMovement', 60);
+  const pos60 = machine.state.getCurrentPosition();
+
+  assert.ok(pos60 > pos30, 'Position at 60 should be greater than at 30');
+});
+
+test('movement to 0 sets flow and power predictions to minimum curve values', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  machine.updateMeasuredPressure(1000, 'downstream', { timestamp: Date.now(), unit: 'mbar', childName: 'pt' });
+
+  await machine.handleInput('parent', 'execMovement', 0);
+
+  const pos = machine.state.getCurrentPosition();
+  assert.equal(pos, 0, 'Position should be at 0');
+});
+
+test('movement is rejected in non-operational state', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+  assert.equal(machine.state.getCurrentState(), 'idle');
+
+  // Attempt movement in idle state — handleInput should process but no movement happens
+  await machine.handleInput('parent', 'execMovement', 50);
+
+  // Machine should still be idle (movement requires operational state via sequence first)
+  assert.equal(machine.state.getCurrentState(), 'idle');
+});