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/service/screenshot/ScreenshotTask.cpp

@@ -107,7 +107,7 @@ void ScreenshotTask::taskStart() {
         return;
     }
 
-    tt_check(thread == nullptr);
+    check(thread == nullptr);
     thread = new Thread(
         "screenshot",
         8192,