Fixes and improvements (#620)

- Standardized keyboard input using Unicode-based key codes across supported devices and the simulator. Keyboards don't emit `LV_KEY_*` anymore.
- Refactored lilygo encoder driver into a reusable GPIO rotary encoder driver (see `Drivers/gpio-encoder-module/`). Added more features to the config file.
- Improved LVGL keyboard device management, including duplicate prevention and reliable reconnects.
- LVGL file mutex now registers with lvgl start/stop
- Improved LVGL startup/shutdown stability and memory allocation reliability.
- Increased simulator LVGL memory capacity and improved USB device-class handling.

Drivers/gpio-encoder-module/include/bindings/gpio_encoder.h

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/bindings/bindings.h>
+#include <drivers/gpio_encoder.h>
+
+DEFINE_DEVICETREE(gpio_encoder, struct GpioEncoderConfig)

Drivers/gpio-encoder-module/include/drivers/gpio_encoder.h

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <tactility/drivers/gpio.h>
+
+struct GpioEncoderConfig {
+    // First pin of encoder wheel
+    struct GpioPinSpec pin_a;
+    // Second pin of encoder wheel
+    struct GpioPinSpec pin_b;
+    // "Button" pin of encoder wheel. Optional: GPIO_PIN_SPEC_NONE when the wheel has no click/enter button.
+    struct GpioPinSpec pin_enter;
+    // Quadrature pulses per mechanical detent (x4 decode gives 4 pulses/detent for a standard EC11-style encoder).
+    uint8_t pulses_per_detent;
+    // Capacity of the queue buffering key events between read_key() polls.
+    uint8_t pending_capacity;
+};
+
+#ifdef __cplusplus
+}
+#endif

Drivers/gpio-encoder-module/include/gpio_encoder_module.h

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/module.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern struct Module gpio_encoder_module;
+
+#ifdef __cplusplus
+}
+#endif