Various improvements (#461)

* **New Features**
  * Time and delay utilities added (ticks, ms, µs); SD card now uses an expansion-header CS pin; HTTP downloads warn when run on the GUI task and yield to avoid blocking.

* **Bug Fixes / Reliability**
  * Many hard-crash paths converted to guarded checks to reduce abrupt termination and improve stability.

* **Tests**
  * Unit tests added to validate time and delay accuracy.

* **Chores**
  * License header and build/macro updates.

Tactility/Source/app/files/View.cpp

@@ -1,12 +1,13 @@
 #include <Tactility/app/files/View.h>
 #include <Tactility/app/files/SupportedFiles.h>
 
-#include <Tactility/file/File.h>
 #include <Tactility/app/alertdialog/AlertDialog.h>
 #include <Tactility/app/imageviewer/ImageViewer.h>
 #include <Tactility/app/inputdialog/InputDialog.h>
 #include <Tactility/app/notes/Notes.h>
 #include <Tactility/app/ElfApp.h>
+#include <Tactility/Check.h>
+#include <Tactility/file/File.h>
 #include <Tactility/kernel/Platform.h>
 #include <Tactility/Logger.h>
 #include <Tactility/LogMessages.h>
@@ -58,7 +59,7 @@ static void onDeletePressedCallback(lv_event_t* event) {
     view->onDeletePressed();
 }
 
-static void onNavigateUpPressedCallback(TT_UNUSED lv_event_t* event) {
+static void onNavigateUpPressedCallback(lv_event_t* event) {
     auto* view = static_cast<View*>(lv_event_get_user_data(event));
     view->onNavigateUpPressed();
 }
@@ -179,7 +180,7 @@ void View::onDirEntryLongPressed(int32_t index) {
 }
 
 void View::createDirEntryWidget(lv_obj_t* list, dirent& dir_entry) {
-    tt_check(list);
+    check(list);
     const char* symbol;
     if (dir_entry.d_type == file::TT_DT_DIR || dir_entry.d_type == file::TT_DT_CHR) {
         symbol = LV_SYMBOL_DIRECTORY;