Clear log if invalid

lib/hal/HalSystem.cpp

@@ -79,7 +79,11 @@ void begin() {
   } 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();
+    // If logHead was out of range, logMessages is also garbage — clear it so
+    // getLastLogs() does not dump corrupt data into the crash report.
+    if (sanitizeLogHead()) {
+      clearLastLogs();
+    }
   }
 }