Migrate _loadConfig to use ConfigManager.buildConfig()

Replaces manual base config construction with shared buildConfig() method.
Node now only specifies domain-specific config sections.

Part of #1: Extract base config schema

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/nodeClass.js

@@ -38,23 +38,14 @@ class nodeClass {
   _loadConfig(uiConfig, node) {
     const cfgMgr = new configManager();
     this.defaultConfig = cfgMgr.getConfig(this.name);
-    const flowUnit = this._resolveUnitOrFallback(uiConfig.unit, 'volumeFlowRate', 'm3/h', 'flow');
 
-    // Merge UI config over defaults
-    this.config = {
-      general: {
-        name: uiConfig.name,
-        id: node.id, // node.id is for the child registration process
-        unit: flowUnit,
-        logging: {
-          enabled: uiConfig.enableLog,
-          logLevel: uiConfig.logLevel,
-        },
-      },
-      functionality: {
-        positionVsParent: uiConfig.positionVsParent || "atEquipment", // Default to 'atEquipment' if not set
-      },
-    };
+    // Resolve flow unit with validation before building config
+    const flowUnit = this._resolveUnitOrFallback(uiConfig.unit, 'volumeFlowRate', 'm3/h', 'flow');
+    const resolvedUiConfig = { ...uiConfig, unit: flowUnit };
+
+    // Build config: base sections (no domain-specific config for group controller)
+    this.config = cfgMgr.buildConfig(this.name, resolvedUiConfig, node.id);
+
     // Utility for formatting outputs
     this._output = new outputUtils();
   }