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/tca8418-module/bindings/ti,tca8418.yaml

@@ -34,8 +34,8 @@ properties:
       Base (lowercase) layer keymap, rows*columns bytes in row-major order (already in
       silkscreen/keymap column order - see reverse-columns). 0 = no key at this position (e.g.
       a blank matrix position, or a position handled as a modifier via shift-row/shift-col/
-      sym-row/sym-col instead). Non-zero bytes are sent as-is via KeyboardKeyData::key (ASCII
-      or an LVGL LV_KEY_* code).
+      sym-row/sym-col instead). Non-zero bytes are sent as-is via KeyboardKeyData::key (a Unicode
+      codepoint - byte range covers Latin-1 - for character and non-character keys).
   keymap-uc:
     type: array
     element-type: uint8_t