Devicetree DTS and YAML format improvements (#492)

* **DevicetreeCompiler**
  * Binding properties now support default values.
  * Compiler returns meaningful exit codes and reports errors more clearly.
  * Stronger validation of device configurations with unified error handling.
  * Added integration tests and a dedicated Devicetree test workflow.

* **Changes**
  * Platform binding schemas updated: some fields made required, others gained explicit defaults.
  * Many device-tree files simplified by removing unused/placeholder pin and transfer-size entries.

* **Documentation**
  * Removed several outdated TODO items.

Devices/m5stack-cores3/m5stack,cores3.dts

@@ -55,9 +55,6 @@
 		pin-mosi = <37>;
 		pin-miso = <35>;
 		pin-sclk = <36>;
-		pin-wp = <GPIO_PIN_NONE>;
-		pin-hd = <GPIO_PIN_NONE>;
-		max-transfer-size = <0>;
 	};
 
 	// TODO: Enable speaker via ES7210 I2C: https://github.com/m5stack/M5Unified/blob/a6256725481f1bc366655fa48cf03b6095e30ad1/src/M5Unified.cpp#L417
@@ -79,7 +76,5 @@
 		port = <UART_NUM_1>;
 		pin-tx = <1>;
 		pin-rx = <2>;
-		pin-cts = <GPIO_PIN_NONE>;
-		pin-rts = <GPIO_PIN_NONE>;
 	};
 };