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/lilygo-module/bindings/lilygo,tpager-encoder.yaml

@@ -1,22 +0,0 @@
-description: >
-  LilyGO T-Lora Pager encoder wheel next to the display - a 2-phase quadrature encoder
-  (decoded via the ESP32 hardware PCNT peripheral) plus a separate click/enter button.
-  Reports raw, unscaled pulses and button level: the pulses-per-detent scaling and enter-press
-  debounce are UI concerns layered on top by the consumer (see tpager_encoder_input.h), not
-  something this driver knows about.
-
-compatible: "lilygo,tpager-encoder"
-
-properties:
-  pin-a:
-    type: phandles
-    required: true
-    description: Quadrature phase A GPIO pin
-  pin-b:
-    type: phandles
-    required: true
-    description: Quadrature phase B GPIO pin
-  pin-enter:
-    type: phandles
-    required: true
-    description: Click/enter button GPIO pin (active low)