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

@@ -12,12 +12,16 @@ module.exports = [
     topic: 'data.influent',
     aliases: ['influent', 'setInfluent'],
     payloadSchema: { type: 'any' },
+    // Compound payload `{F, C: [...]}` — registry-level units normalisation is
+    // skipped (the handler converts per-field internally; flow=m3/h, conc=mg/L).
+    description: 'Push the influent stream (payload: {F: flow m3/h, C: [concentrations mg/L]}).',
     handler: handlers.dataInfluent,
   },
   {
     topic: 'child.register',
     aliases: ['registerChild'],
     payloadSchema: { type: 'string' },
+    description: 'Register a child node (typically a measurement) with this settler.',
     handler: handlers.childRegister,
   },
 ];