fix: shutdown clears delayedMove so abort+autoPickup can't re-engage pump

When PS commanded turnOffAllMachines, executeSequence's interruptible
abort path triggered transitionToState('operational'), which auto-picked
up the queued delayedMove and re-started the pump. Pump bounced
accelerating ↔ decelerating forever and never reached idle.

Clear state.delayedMove at the top of shutdown/emergencystop sequences
so a user-commanded stop cancels any pending move.

Observed live: in pumpingstation-complete-example the basin drained
past stopLevel and equilibrated at ~0.3 m with one pump stuck at min
flow. With this fix pumps shut down cleanly at stopLevel.

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

test/integration/shutdown-sequence.integration.test.js

@@ -70,3 +70,77 @@ test('exitmaintenance requires mode with exitmaintenance action allowed', async
   await machine.handleInput('fysical', 'exitMaintenance', 'exitmaintenance');
   assert.equal(machine.state.getCurrentState(), 'idle');
 });
+
+test('shutdown clears delayedMove synchronously, before the abort/await path runs', async () => {
+  // Regression: when MGC parks a setpoint in state.delayedMove during a
+  // dead-zone keep-alive, then PS commands shutdown via turnOffAllMachines,
+  // the shutdown's interruptible-abort path triggers transitionToState
+  // ('operational'), which auto-picks up delayedMove and re-starts the
+  // pump. Pump bounces accelerating ↔ decelerating forever and the
+  // shutdown sequence never reaches idle. Observed live in the
+  // pumpingstation-complete-example demo: basin drained past stopLevel
+  // with one pump stuck at minimum flow.
+  //
+  // Fix: executeSequence clears state.delayedMove for shutdown/emergencystop
+  // BEFORE the abort+await path. Asserting synchronously (race the first
+  // microtask) is the precise behavioural check — without the fix, the
+  // auto-pickup could still re-engage the pump on the way to idle even if
+  // the value is null after the call returns.
+
+  const slowMove = makeStateConfig({
+    movement: { mode: 'staticspeed', speed: 50, maxSpeed: 100, interval: 10 },
+  });
+  const machine = new Machine(makeMachineConfig(), slowMove);
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  assert.equal(machine.state.getCurrentState(), 'operational');
+  machine.setpoint(80);
+  await new Promise((r) => setTimeout(r, 50));
+  assert.equal(machine.state.getCurrentState(), 'accelerating');
+
+  machine.state.delayedMove = 75;
+
+  // Kick off the shutdown but do not await — capture state before the
+  // abort path's await yields.
+  const shutdownPromise = machine.handleInput('parent', 'execSequence', 'shutdown');
+  // Yield once to allow the synchronous prelude of executeSequence to run
+  // (lookup, lowercase, the new delayedMove=null assignment) without
+  // letting any await resolve.
+  await Promise.resolve();
+  assert.equal(machine.state.delayedMove, null,
+    'delayedMove must be cleared synchronously by the shutdown prelude — otherwise the abort path will auto-pick it up');
+
+  await shutdownPromise;
+  assert.equal(machine.state.getCurrentState(), 'idle');
+});
+
+test('emergencystop also clears queued delayedMove', async () => {
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  await machine.handleInput('parent', 'execMovement', 30);
+  machine.state.delayedMove = 60;
+
+  await machine.handleInput('parent', 'execSequence', 'emergencystop');
+
+  assert.equal(machine.state.delayedMove, null,
+    'emergency-stop must clear delayedMove');
+});
+
+test('startup does NOT clear delayedMove (only shutdown/emergencystop does)', async () => {
+  // delayedMove serves a legitimate purpose for non-stop sequences — e.g.
+  // setpoints arriving while the pump is in 'starting' get queued and
+  // auto-picked-up when state lands in 'operational'. The fix must be
+  // narrowly scoped to interruptible (stop) sequences.
+  const machine = new Machine(makeMachineConfig(), makeStateConfig());
+
+  await machine.handleInput('parent', 'execSequence', 'startup');
+  machine.state.delayedMove = 42;
+
+  // Re-running startup from operational is a no-op for state, but the
+  // delayedMove must still be there afterwards for the auto-pickup to fire.
+  await machine.handleInput('parent', 'execSequence', 'startup');
+
+  assert.equal(machine.state.delayedMove, 42,
+    'non-stop sequences must preserve delayedMove for the auto-pickup');
+});