feat(state): honor sequenceAbortToken so external aborts cleanly break sequences

Consumer half of the abort-token mechanism added in generalFunctions
state.js. executeSequence captures host.state.sequenceAbortToken at
entry, then re-checks before every state transition and after the
optional ramp-down. If MGC (or any external caller) bumps the token
mid-sequence, the loop bails out cleanly — no more barge-through where
a pre-empted shutdown advances through stopping → coolingdown after a
fresh demand has already engaged the pump.

Without this the MGC rendezvous planner can't reliably re-dispatch a
pump that's mid-shutdown: the new flowmovement claims the gate, but
the old shutdown's for-loop keeps running on microtasks and steps the
FSM into idle/off underneath it.

Also: wiki regen following the same visual-first 14-section template as
the other EVOLV nodes — Reference-{Architecture,Contracts,Examples,
Limitations}.md split with _Sidebar.md index.

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

src/state/sequenceController.js

@@ -63,6 +63,15 @@ async function executeSequence(host, rawName) {
     host.logger.warn(`Sequence '${name}' not defined.`);
     return;
   }
+  // Snapshot the sequence-abort token at entry, BEFORE any awaits. If an
+  // external abort advances the counter while we're inside this call
+  // (setpoint ramp-down, waitForOperational, or the state transition
+  // loop), every check below sees the mismatch and breaks out so the
+  // new dispatch can claim the FSM. Capturing later would conflate the
+  // abort that fired during setpoint(0) with the initial entry state.
+  const startToken = host.state.sequenceAbortToken ?? 0;
+  const aborted = () => (host.state.sequenceAbortToken ?? 0) !== startToken;
+
   const interruptible = new Set(['shutdown', 'emergencystop']);
   if (interruptible.has(name)) host.state.delayedMove = null;
   const current = host.state.getCurrentState();
@@ -74,9 +83,18 @@ async function executeSequence(host, rawName) {
   if (host.state.getCurrentState() === 'operational' && name === 'shutdown') {
     host.logger.info(`Machine will ramp down to position 0 before performing ${name} sequence`);
     await setpoint(host, 0);
+    if (aborted()) {
+      host.logger.warn(`Sequence '${name}' interrupted during ramp-down by external abort; not entering shutdown loop.`);
+      host.updatePosition();
+      return;
+    }
   }
   host.logger.info(` --------- Executing sequence: ${name} -------------`);
   for (const s of sequence) {
+    if (aborted()) {
+      host.logger.warn(`Sequence '${name}' interrupted at step '${s}' by external abort; stopping further transitions.`);
+      break;
+    }
     try { await host.state.transitionToState(s); }
     catch (e) { host.logger.error(`Error during sequence '${name}': ${e}`); break; }
   }