get_device_warnings() now returns only {code, meta} — severity, title,
message, and action are resolved centrally by netork's
WARNING_CATALOG (netork/core/device_warnings.py), not by the driver.
Keeps this driver independent of netork and avoids per-vendor drift in
how the same warning code is presented.
The TYPE_LABEL attribute on the base class hierarchy is now the
canonical way for drivers to declare their device category. The
storage_device sentinel flag is removed — classification is determined
by reading TYPE_LABEL via getattr() in the backend.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>