P6: convert dashboardAPI to platform infrastructure

Refactor of dashboardAPI to use BaseNodeAdapter + commandRegistry + statusBadge.
dashboardAPI follows the platform refactor plan in .claude/refactor/MODULE_SPLIT.md.
Tests stay green; CONTRACT.md generated; legacy aliases preserved.

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

src/commands/handlers.js

@@ -0,0 +1,64 @@
+'use strict';
+
+// Resolve a child's source object from a registration payload.
+// Payload may be: a string (node id) | { source: {...} } | { config: {...} }.
+function resolveChildSource(payload, ctx) {
+  if (payload?.source?.config) return payload.source;
+  if (payload?.config) return { config: payload.config };
+  if (typeof payload === 'string') {
+    const childNode = resolveChildNode(payload, ctx);
+    return childNode?.source || null;
+  }
+  return null;
+}
+
+function resolveChildNode(childId, ctx) {
+  const runtimeNode = ctx.RED?.nodes?.getNode?.(childId);
+  if (runtimeNode?.source?.config) return runtimeNode;
+
+  const flowNode = ctx.node?._flow?.getNode?.(childId);
+  if (flowNode?.source?.config) return flowNode;
+
+  return runtimeNode || flowNode || null;
+}
+
+// On child.register: build the dashboard graph (root + direct children) and
+// emit one Grafana upsert HTTP request per dashboard on Port 0.
+function registerChild(source, msg, ctx) {
+  const childSource = resolveChildSource(msg.payload, ctx);
+  if (!childSource?.config) {
+    throw new Error('Missing or invalid child node');
+  }
+
+  const dashboards = source.generateDashboardsForGraph(childSource, {
+    includeChildren: Boolean(msg.includeChildren ?? true),
+  });
+
+  const url = source.grafanaUpsertUrl();
+  const headers = { Accept: 'application/json', 'Content-Type': 'application/json' };
+  const token = source.config?.grafanaConnector?.bearerToken;
+  if (token) headers.Authorization = `Bearer ${token}`;
+
+  for (const dash of dashboards) {
+    ctx.send({
+      ...msg,
+      topic: 'create',
+      url,
+      method: 'POST',
+      headers,
+      payload: source.buildUpsertRequest({
+        dashboard: dash.dashboard,
+        folderId: 0,
+        overwrite: true,
+      }),
+      meta: {
+        nodeId: dash.nodeId,
+        softwareType: dash.softwareType,
+        uid: dash.uid,
+        title: dash.title,
+      },
+    });
+  }
+}
+
+module.exports = { registerChild };