I2S driver implementation (#480)

* **New Features**
  * ESP32 I2S controller support: runtime-configurable digital audio I/O with read/write/set/get operations and multiple formats.

* **Board Support**
  * LilyGO T-Deck device tree entry added to enable I2S peripheral pin configuration.

* **Documentation**
  * New/updated bindings and descriptors for I2S, I2C, GPIO, and root nodes.

* **Other**
  * Added GPIO "no pin" sentinel and exposed I2S controller API symbols.

TactilityKernel/Source/drivers/i2s_controller.cpp

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <tactility/drivers/i2s_controller.h>
+#include <tactility/error.h>
+#include <tactility/device.h>
+
+#define I2S_DRIVER_API(driver) ((struct I2sControllerApi*)driver->api)
+
+extern "C" {
+
+error_t i2s_controller_read(Device* device, void* data, size_t dataSize, size_t* bytesRead, TickType_t timeout) {
+    const auto* driver = device_get_driver(device);
+    return I2S_DRIVER_API(driver)->read(device, data, dataSize, bytesRead, timeout);
+}
+
+error_t i2s_controller_write(Device* device, const void* data, size_t dataSize, size_t* bytesWritten, TickType_t timeout) {
+    const auto* driver = device_get_driver(device);
+    return I2S_DRIVER_API(driver)->write(device, data, dataSize, bytesWritten, timeout);
+}
+
+error_t i2s_controller_set_config(Device* device, const struct I2sConfig* config) {
+    const auto* driver = device_get_driver(device);
+    return I2S_DRIVER_API(driver)->set_config(device, config);
+}
+
+error_t i2s_controller_get_config(Device* device, struct I2sConfig* config) {
+    const auto* driver = device_get_driver(device);
+    return I2S_DRIVER_API(driver)->get_config(device, config);
+}
+
+error_t i2s_controller_reset(struct Device* device) {
+    const auto* driver = device_get_driver(device);
+    return I2S_DRIVER_API(driver)->reset(device);
+}
+
+extern const struct DeviceType I2S_CONTROLLER_TYPE { 0 };
+
+}