Add and expose sanitizing logic

lib/hal/HalSystem.cpp

@@ -76,6 +76,10 @@ void begin() {
   // `clearPanic()` to clear it after dumping
   if (!isRebootFromPanic()) {
     clearPanic();
+  } else {
+    // Panic reboot: preserve logs and panic info, but clamp logHead in case the
+    // panic occurred before begin() ever ran (e.g. in a static constructor).
+    sanitizeLogHead();
   }
 }