read() reports FILE_NOT_FOUND status for unrelated file I/O errors #578

Hi @pradeeban, found a small bug while reading through concore_base.py's file-based read().

When the port file fails to open, FileNotFoundError is handled separately, but any other error (permission denied, reading a directory, a corrupted file that can't decode, etc.) falls into the generic except and still sets last_read_status = "FILE_NOT_FOUND", even though the file exists and something else went wrong.

Kind of defeats the purpose of read_with_status() (#390/#498), which exists so callers know why they got default data. In a control loop, "no data yet" and "something's actually broken" aren't the same thing.

Also, the docstring lists EMPTY_DATA as a possible status, but nothing in the file ever sets it. Looks like stale documentation.

tests/test_read_status.py doesn't cover this case either.

Happy to send a PR: proper status for that branch, fix the EMPTY_DATA docstring, and a regression test.