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.

TactilityKernel/Source/concurrent/EventGroup.cpp

@@ -48,7 +48,7 @@ error_t event_group_wait(
     uint32_t* outFlags,
     TickType_t timeout
 ) {
-    if (xPortInIsrContext()) {
+    if (xPortInIsrContext() == pdTRUE) {
         return ERROR_ISR_STATUS;
     }