New kernel drivers, filesystem API, and more (#513)

* **New Features**
  * BMI270 6-axis IMU driver added; new unified filesystem abstraction for mounted filesystems.
  * Public Wi‑Fi API surface (no implementation yet)
  * SDMMC driver added (kernel drive$)
  * expanded GPIO interrupt/callback support
* **Improvements**
  * M5Stack Tab5: revamped GPIO/power initialization and IMU integration.
  * LVGL updates including device fontSize configuration.
  * Updated all code related to SD card device/fs handling
  * Rename LilyGO T-HMI S3 to LilyGO T-HMI
* **Bug Fixes**
  * Simplified and consolidated SD card handling and mount discovery.

TactilityKernel/source/filesystem/file_system.cpp

@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include <algorithm>
+#include <tactility/concurrent/mutex.h>
+#include <tactility/concurrent/recursive_mutex.h>
+#include <tactility/filesystem/file_system.h>
+#include <vector>
+
+// Define the internal FileSystem structure
+struct FileSystem {
+    const FileSystemApi* api;
+    void* data;
+};
+
+// Global list of file systems and its mutex
+struct FileSystemsLedger {
+    std::vector<FileSystem*> file_systems;
+    // Use recursive mutex so that file_system_for_each() can lock within the callback
+    RecursiveMutex mutex {};
+
+    FileSystemsLedger() { recursive_mutex_construct(&mutex); }
+    ~FileSystemsLedger() { recursive_mutex_destruct(&mutex); }
+
+    void lock() { recursive_mutex_lock(&mutex); }
+    bool is_locked() { return recursive_mutex_is_locked(&mutex); }
+    void unlock() { recursive_mutex_unlock(&mutex); }
+};
+
+static FileSystemsLedger& get_ledger() {
+    static FileSystemsLedger ledger;
+    return ledger;
+}
+
+extern "C" {
+
+FileSystem* file_system_add(const FileSystemApi* fs_api, void* data) {
+    auto& ledger = get_ledger();
+    check(!ledger.is_locked()); // ensure file_system_for_each() doesn't add a filesystem while iterating
+    ledger.lock();
+    
+    auto* fs = new(std::nothrow) struct FileSystem();
+    check(fs != nullptr);
+    fs->api = fs_api;
+    fs->data = data;
+    ledger.file_systems.push_back(fs);
+    
+    ledger.unlock();
+    return fs;
+}
+
+void file_system_remove(FileSystem* fs) {
+    check(!file_system_is_mounted(fs));
+    auto& ledger = get_ledger();
+    check(!ledger.is_locked()); // ensure file_system_for_each() doesn't remove a filesystem while iterating
+    ledger.lock();
+    
+    auto it = std::ranges::find(ledger.file_systems, fs);
+    if (it != ledger.file_systems.end()) {
+        ledger.file_systems.erase(it);
+        delete fs;
+    }
+    
+    ledger.unlock();
+}
+
+void file_system_for_each(void* callback_context, bool (*callback)(FileSystem* fs, void* context)) {
+    auto& ledger = get_ledger();
+    ledger.lock();
+    for (auto* fs : ledger.file_systems) {
+        if (!callback(fs, callback_context)) break;
+    }
+    ledger.unlock();
+}
+
+error_t file_system_mount(FileSystem* fs) {
+    // Assuming 'device' is accessible or passed via a different mechanism
+    // as it's required by the FileSystemApi signatures.
+    return fs->api->mount(fs->data);
+}
+
+error_t file_system_unmount(FileSystem* fs) {
+    return fs->api->unmount(fs->data);
+}
+
+bool file_system_is_mounted(FileSystem* fs) {
+    return fs->api->is_mounted(fs->data);
+}
+
+error_t file_system_get_path(FileSystem* fs, char* out_path, size_t out_path_size) {
+    return fs->api->get_path(fs->data, out_path, out_path_size);
+}
+
+}