fix: expose tick(dt) on Reactor wrapper

P6.5 refactor introduced the BaseDomain wrapper around CSTR/PFR engines
but didn't pass tick() through. BaseNodeAdapter's optional-chain
source.tick?.() got undefined and the kinetics engine never integrated
when driven through the new adapter (only via the explicit
_emitOutputs override that calls updateState).

Added tick(timeStep) that delegates to engine.tick + emits
'output-changed'. Tests that construct the wrapper (not the engine
directly) now work.

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

src/specificClass.js

@@ -75,6 +75,16 @@ class Reactor extends BaseDomain {
 
   updateState(t) { this.engine.updateState(t); this.notifyOutputChanged(); }
 
+  // Engine pass-through — needed so the BaseNodeAdapter tick loop (and
+  // tests calling reactor.tick(dt) directly) drive the ASM integration.
+  // Without this the Node-RED tick fires `source.tick?.()`, gets undefined,
+  // and the kinetics state never advances.
+  tick(timeStep) {
+    const result = this.engine.tick(timeStep);
+    this.notifyOutputChanged();
+    return result;
+  }
+
   get getEffluent()    { return this.engine.getEffluent; }
   get getGridProfile() { return this.engine.getGridProfile; }
   get temperature()    { return this.engine.temperature; }