P11.3 + P11.4: BaseNodeAdapter query.units + wikiGen Unit column

P11.3 BaseNodeAdapter auto-wires query.units:
  Implicit query.units topic registered if subclass commands don't
  already declare one. Returns {node, units: {topic → {measure,
  default, accepted: [...]}}} via convert.possibilities. Subclass
  query.units overrides. 17/17 tests; BaseNodeAdapter.js 211 lines.

P11.4 wikiGen Unit column:
  Auto-generated topic-contract table grows a Unit column showing
  `<measure> (default <unit>)` for topics with units, '—' otherwise.
  Effect column now uses descriptor.description when present (P11.2
  field), falls back to generic per-prefix sentence. wikiGen.js 303
  → 315 lines. WIKI_TEMPLATE.md §5 sample updated.

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

src/nodered/BaseNodeAdapter.js

@@ -18,9 +18,36 @@ const ConfigManager = require('../configs/index.js');
 const OutputUtils = require('../helper/outputUtils.js');
 const { createRegistry } = require('./commandRegistry.js');
 const { StatusUpdater } = require('./statusUpdater.js');
+const convert = require('../convert');
 
 const REGISTRATION_DELAY_MS = 100;
 
+function _buildImplicitUnitsCommand(getCommands, getNodeName) {
+    return {
+        topic: 'query.units',
+        payloadSchema: { type: 'any' },
+        description: 'Returns the unit spec (measure, default, accepted) for every topic that declares units.',
+        handler: (source, msg, ctx) => {
+            const units = {};
+            for (const d of getCommands()) {
+                if (!d.units) continue;
+                const accepted = (convert && typeof convert.possibilities === 'function')
+                    ? convert.possibilities(d.units.measure) : [];
+                units[d.topic] = {
+                    measure: d.units.measure,
+                    default: d.units.default,
+                    accepted,
+                };
+            }
+            const reply = Object.assign({}, msg, {
+                topic: 'query.units',
+                payload: { node: getNodeName(), units },
+            });
+            if (ctx && typeof ctx.send === 'function') ctx.send([reply, null, null]);
+        },
+    };
+}
+
 class BaseNodeAdapter {
     constructor(uiConfig, RED, nodeInstance, nameOfNode) {
         const ctor = this.constructor;
@@ -56,7 +83,15 @@ class BaseNodeAdapter {
         this.node.source = this.source;
 
         this._output = new OutputUtils();
-        this._commands = createRegistry(ctor.commands, { logger: this.source?.logger });
+        const userHasUnitsQuery = ctor.commands.some(
+            (c) => c && (c.topic === 'query.units' || (Array.isArray(c.aliases) && c.aliases.includes('query.units'))));
+        const mergedCommands = userHasUnitsQuery
+            ? ctor.commands
+            : ctor.commands.concat([_buildImplicitUnitsCommand(
+                () => this._commands.list(),
+                () => this.name,
+            )]);
+        this._commands = createRegistry(mergedCommands, { logger: this.source?.logger });
 
         this._tickInterval = null;
         this._outputChangedListener = null;