Fixes and improvements (#185)

- unPhone improvements related to power and boot (add boot count logging)
- Cleanup of Mutex acquire/release
- Removed `tt_assert()` in favour of `assert()`
- Fix sim build (likely failed due to migration of GitHub Actions to Ubuntu 24.04)

CODING_STYLE.md

@@ -51,7 +51,7 @@ void getLimit() {
 Preprocessor functions are written in snake-case and prefixed with `tt_`, for example:
 
 ```c++
-#define tt_assert(x) __tt_assert_internal(x)
+#define tt_check(x) if (!(x)) { /* .. */ }
 ```
 
 ### Type names