* **New Features**
* Added a standalone LVGL module and enabled LVGL support in the simulator for richer local UI testing.
* **Refactor**
* HAL and LVGL split into distinct modules; startup and device attach/detach flows reorganized for clearer lifecycle management.
* Public APIs tightened with clearer nullability/documentation.
* **Bug Fixes**
* More consistent LVGL start/stop and device attach/detach behavior for improved stability.
* **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.
