Improve led-tool flashing and settings flow

Made-with: Cursor

lib/mpremote/mp_errno.py

@@ -1,5 +1,9 @@
 import errno
-import platform
+
+try:
+    import platform
+except Exception:  # MicroPython or restricted envs
+    platform = None
 
 # This table maps numeric values defined by `py/mperrno.h` to host errno code.
 MP_ERRNO_TABLE = {
@@ -51,5 +55,5 @@ MP_ERRNO_TABLE = {
     115: errno.EINPROGRESS,
     125: errno.ECANCELED,
 }
-if platform.system() != "Windows":
+if (platform.system() if platform else None) != "Windows":
     MP_ERRNO_TABLE[15] = errno.ENOTBLK