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/0.Structures/struct_boiler_status.st

@@ -0,0 +1,22 @@
+(* === DECLARATION === *)
+TYPE struct_boiler_status :
+STRUCT
+    // State
+    state: BOOL;              // Current boiler state (ON/OFF)
+    relay_output: BOOL;       // Actual relay output state
+    
+    // Runtime Info
+    on_time_minutes: INT;     // Current ON time in minutes
+    remaining_minutes: INT;   // Remaining time before auto-shutoff
+    
+    // Safety Status
+    emergency_active: BOOL;   // Emergency stop is active
+    time_limit_reached: BOOL; // Max time limit was reached
+    
+    // Error Handling
+    error_state: BOOL;        // Error detected
+    error_code: INT;          // Error code (0=none, 1=emergency, 2=time limit)
+END_STRUCT
+END_TYPE
+
+(* === IMPLEMENTATION === *)