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/screenshot/Screenshot.cpp

@@ -58,14 +58,14 @@ std::shared_ptr<ScreenshotApp> _Nullable optApp() {
     }
 }
 
-static void onStartPressedCallback(TT_UNUSED lv_event_t* event) {
+static void onStartPressedCallback(lv_event_t* event) {
     auto app = optApp();
     if (app != nullptr) {
         app->onStartPressed();
     }
 }
 
-static void onModeSetCallback(TT_UNUSED lv_event_t* event) {
+static void onModeSetCallback(lv_event_t* event) {
     auto app = optApp();
     if (app != nullptr) {
         app->onModeSet();