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.

Modules/lvgl-module/source/lv_mem_custom.c

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: Apache-2.0
+// LVGL's custom stdlib allocator backend (LV_STDLIB_CUSTOM / CONFIG_LV_USE_CUSTOM_MALLOC) - routes
+// lv_malloc()/lv_realloc()/lv_free() through the kernel's memory_*_with_policy() functions instead
+// of a fixed-size private pool (LV_STDLIB_BUILTIN) or plain malloc (LV_STDLIB_CLIB), so LVGL grows
+// dynamically and prefers PSRAM when available instead of contending with everything else for a
+// small, fixed internal-RAM arena.
+#include <lvgl/lvgl.h>
+#include <tactility/memory.h>
+
+// PSRAM is preferred, not required: MEMORY_CAPABILITY_EXTERNAL is `desired`, so
+// memory_alloc_with_policy()/memory_realloc_with_policy() fall back to internal RAM automatically
+// on boards without PSRAM, or if PSRAM is exhausted.
+static const struct MemoryPolicy LVGL_MEMORY_POLICY = {
+    .required = 0,
+    .desired = MEMORY_CAPABILITY_EXTERNAL,
+    .alignment = 0,
+};
+
+void lv_mem_init(void) {
+}
+
+void lv_mem_deinit(void) {
+}
+
+lv_mem_pool_t lv_mem_add_pool(void* mem, size_t bytes) {
+    // Not supported - memory_*_with_policy() owns allocation, LVGL doesn't need to manage its own
+    // pools on top of it.
+    (void)mem;
+    (void)bytes;
+    return NULL;
+}
+
+void lv_mem_remove_pool(lv_mem_pool_t pool) {
+    (void)pool;
+}
+
+void* lv_malloc_core(size_t size) {
+    return memory_alloc_with_policy(size, &LVGL_MEMORY_POLICY);
+}
+
+void* lv_realloc_core(void* p, size_t new_size) {
+    return memory_realloc_with_policy(p, new_size, &LVGL_MEMORY_POLICY);
+}
+
+void lv_free_core(void* p) {
+    memory_free(p);
+}
+
+void lv_mem_monitor_core(lv_mem_monitor_t* mon_p) {
+    // Not supported - memory_*_with_policy() doesn't expose LVGL-specific usage/fragmentation
+    // stats (memory_print_stats() covers overall heap state instead).
+    (void)mon_p;
+}
+
+lv_result_t lv_mem_test_core(void) {
+    return LV_RESULT_OK;
+}