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.

TactilityCore/CMakeLists.txt

@@ -6,7 +6,7 @@ if (DEFINED ENV{ESP_IDF_VERSION})
     idf_component_register(
         SRCS ${SOURCE_FILES}
         INCLUDE_DIRS "Include/"
-        REQUIRES TactilityFreeRtos mbedtls nvs_flash esp_rom
+        REQUIRES TactilityFreeRtos TactilityKernel mbedtls nvs_flash esp_rom
     )
 
     if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
@@ -26,8 +26,9 @@ else()
     add_definitions(-D_Nullable=)
     add_definitions(-D_Nonnull=)
 
-    target_link_libraries(TactilityCore
-        PUBLIC TactilityFreeRtos
-        PUBLIC mbedtls
+    target_link_libraries(TactilityCore PUBLIC
+        TactilityFreeRtos
+        TactilityKernel
+        mbedtls
     )
 endif()