P11.5 + B2.1/B2.2: per-command units + description (where applicable)

Adds  to scalar setters whose payloads are
plain numbers OR {value, unit}. Skipped where payload is compound or
mode-dependent (control-%, {F, C: [...]}, etc.) — documented inline.
Every command gains a description field for wikiGen consumption.

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

test/integration/shifted-ramp-end-to-end.test.js

@@ -50,17 +50,34 @@ function makeConfig() {
   };
 }
 
+// machineGroups is a registry-backed getter (declareChildGetter) — inject
+// the fake MGC via the real child-registration handshake so the registry
+// stays the source of truth across configure() and tick().
+function registerMockGroup(ps, id, demands) {
+  const mock = {
+    config: {
+      general: { id, name: id },
+      functionality: { softwareType: 'machinegroup', positionVsParent: 'atEquipment' },
+      asset: { category: 'controller' },
+    },
+    measurements: {
+      emitter: { on: () => {} },
+      setChildId: () => {}, setChildName: () => {}, setParentRef: () => {},
+    },
+    handleInput: async (_src, d) => { demands.push(d); },
+    turnOffAllMachines: () => {},
+  };
+  ps.childRegistrationUtils.registerChild(mock, 'atEquipment');
+  return mock;
+}
+
 // Build a PS with a fake MGC that captures every demand sent to it,
 // and a clock we control so _updatePredictedVolume integrates over a
 // known dt regardless of wall-clock.
 function buildHarness() {
   const ps = new PumpingStation(makeConfig());
   const demands = [];
-  ps.machineGroups['mgc1'] = {
-    config: { general: { name: 'mgc1' } },
-    turnOffAllMachines: () => {},
-    handleInput: async (_src, d) => { demands.push(d); },
-  };
+  registerMockGroup(ps, 'mgc1', demands);
   // Seed level at startLevel so the run begins idle.
   ps.calibratePredictedLevel(2.0);
   // Override Date.now via a controllable clock that advances `step()`.