refactor: sync from template - ENABLE/DISABLE macro pattern

- board_config.h: replace #define/#undef with ENABLE/DISABLE constants
- All debug switches use ENABLE/DISABLE instead of define/undef
- Replace #ifdef with #if MACRO == ENABLE across all sources
- Sync updated README documentation

Src/main.c

@@ -62,15 +62,15 @@ int main(void)
 
     i2c_config();
 
-#ifdef DEBUG_MODE
+#if DEBUG_MODE == ENABLE
     printf("Hello World!\r\n");
 #endif
 
-#ifdef SEGGER_RTT_DETECTION
+#if SEGGER_RTT_DETECTION == ENABLE
     RTT_printf(0, "Hello World!\r\n");
 #endif
 
-#ifdef DEBUG_VERBOSE
+#if DEBUG_VERBOSE == ENABLE
     i2c_scan();
 
     i2c_bus_reset();