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.

TactilityKernel/source/filesystem/file_mutex.cpp

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: Apache-2.0
 #include <tactility/filesystem/file_mutex.h>
+#include <tactility/concurrent/mutex.h>
 
+#include <algorithm>
 #include <cstring>
 #include <string>
 #include <vector>
@@ -12,41 +14,89 @@ static const FileMutex no_mutex = {
 };
 
 struct FileMutexEntry {
+    FileMutexId id;
     std::string path;
     FileMutex mutex;
 };
 
-static std::vector<FileMutexEntry> mutex_entries;
+// Guards mutex_entries against concurrent add/get/remove; unrelated to whether a FileMutex's own
+// lock/unlock is currently held (file_mutex_get() hands out a copy that stays valid regardless of
+// later registry changes - see file_mutex_remove()).
+struct FileMutexLedger {
+    std::vector<FileMutexEntry> entries;
+    FileMutexId next_id = 1;
+    Mutex mutex {};
+
+    FileMutexLedger() { mutex_construct(&mutex); }
+    ~FileMutexLedger() { mutex_destruct(&mutex); }
+
+    void lock() { mutex_lock(&mutex); }
+    void unlock() { mutex_unlock(&mutex); }
+};
+
+static FileMutexLedger& get_ledger() {
+    static FileMutexLedger ledger;
+    return ledger;
+}
 
 extern "C" {
 
-void file_mutex_register(const FileMutex* mutex, const char* path) {
-    // Skip if entry for path exists
-    for (auto& entry : mutex_entries) {
+FileMutexId file_mutex_add(const FileMutex* mutex, const char* path) {
+    auto& ledger = get_ledger();
+    ledger.lock();
+
+    for (auto& entry : ledger.entries) {
         if (entry.path == path) {
-            return;
+            FileMutexId existing_id = entry.id;
+            ledger.unlock();
+            return existing_id;
         }
     }
 
-    // Store a copy of the entry
-    mutex_entries.push_back({
+    FileMutexId new_id = ledger.next_id++;
+    ledger.entries.push_back({
+        .id = new_id,
         .path = path,
         .mutex = *mutex
     });
+
+    ledger.unlock();
+    return new_id;
+}
+
+void file_mutex_remove(FileMutexId id) {
+    auto& ledger = get_ledger();
+    ledger.lock();
+
+    const auto iterator = std::ranges::find_if(ledger.entries, [id](const FileMutexEntry& entry) {
+        return entry.id == id;
+    });
+    if (iterator != ledger.entries.end()) {
+        // Plain erase, not swap-and-pop: file_mutex_get() matches first-registered-wins, so
+        // removal must preserve the relative order of the remaining entries.
+        ledger.entries.erase(iterator);
+    }
+
+    ledger.unlock();
 }
 
 void file_mutex_get(FileMutex* mutex, const char* path) {
+    auto& ledger = get_ledger();
     std::string path_string = path;
-    for (auto& entry : mutex_entries) {
+
+    ledger.lock();
+    for (auto& entry : ledger.entries) {
         // Match the mount path itself, or a descendant (e.g. "/sdcard" registered, "/sdcard/config.json" requested).
         bool is_match = path_string == entry.path ||
             (entry.path == "/" && !path_string.empty() && path_string[0] == '/') ||
             (path_string.rfind(entry.path, 0) == 0 && path_string[entry.path.size()] == '/');
         if (is_match) {
             memcpy(mutex, &entry.mutex, sizeof(FileMutex));
+            ledger.unlock();
             return;
         }
     }
+    ledger.unlock();
 
     *mutex = no_mutex;
 }