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.

TactilityC/Source/tt_app.cpp

@@ -28,7 +28,7 @@ void tt_app_register(
         reinterpret_cast<tt::app::OnResult>(appRegistration.onResult)
     );
 #else
-    tt_crash("TactilityC is not intended for PC/Simulator");
+    check(false, "TactilityC is not intended for PC/Simulator");
 #endif
 }