Initial commit: CODESYS tree, integration docs, Node-RED scripts.

PLC application sources (NVL, rooms, boiler), HA/Node-RED integration guide, and NVL patch utilities.

Co-authored-by: Cursor <cursoragent@cursor.com>

codesys-tree/Device/Plc Logic/Application/1.Variables/GVL.st

@@ -0,0 +1,8 @@
+(* === DECLARATION === *)
+{attribute 'qualified_only'}
+VAR_GLOBAL
+	    // ---------- Option C: relay feedback (copy of output) ----------
+
+END_VAR
+
+(* === IMPLEMENTATION === *)