A stale venv after a code update (editable install + git pull) left
pyserial out of the environment, and the hard module-level import in
wireview.py took the entire web server down — even on machines without
a WireView device.
Guard the import: without pyserial the serial transport is disabled
(one-time warning, connect fails, reads return None) while the rest of
the server keeps running. The hwmon transport is unaffected.
Also simplify the except clauses to OSError (SerialException is an
OSError subclass) so they no longer reference the possibly-None module.
ARIA
b8e91e3c91