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>

src/commands/index.js

@@ -12,36 +12,43 @@ module.exports = [
     topic: 'data.flow',
     aliases: ['air_flow'],
     payloadSchema: { type: 'number' },
+    units: { measure: 'volumeFlowRate', default: 'm3/h' },
+    description: 'Push the measured air flow into the diffuser model.',
     handler: handlers.setFlow,
   },
   {
     topic: 'set.density',
     aliases: ['density'],
     payloadSchema: { type: 'number' },
+    description: 'Update the air density used in OTR / SOTR calculations.',
     handler: handlers.setDensity,
   },
   {
     topic: 'set.water-height',
     aliases: ['height_water'],
     payloadSchema: { type: 'number' },
+    description: 'Update the water column height above the diffusers (m).',
     handler: handlers.setWaterHeight,
   },
   {
     topic: 'set.header-pressure',
     aliases: ['header_pressure'],
     payloadSchema: { type: 'number' },
+    description: 'Update the header (supply) pressure feeding the diffusers (mbar).',
     handler: handlers.setHeaderPressure,
   },
   {
     topic: 'set.elements',
     aliases: ['elements'],
     payloadSchema: { type: 'number' },
+    description: 'Update the count of active diffuser elements.',
     handler: handlers.setElements,
   },
   {
     topic: 'set.alfa-factor',
     aliases: ['alfaFactor'],
     payloadSchema: { type: 'number' },
+    description: 'Update the alfa factor used in oxygen-transfer correction.',
     handler: handlers.setAlfaFactor,
   },
 ];