localthings mints its client cert at runtime through the HA config flow
and never writes it to disk. DtlsCoapSession only accepted cert_path/
key_path (file-based), which would have forced localthings to write its
in-memory cert/key to disk on every connect just to migrate off its
vendored copy of this transport layer.
Adds an alternate cert_pem/key_pem constructor path (ported from
localthings' own _load_pem_chain), validated so exactly one cert source
(file pair or PEM pair) is required. Existing file-path callers
(mqtt_demo, setup_cert.py) are unaffected — verified against both real
appliances with each constructor path.
Marc Billow
a2dc524c0b