A BLE companion that requires pairing accepts the link-layer connection but rejects
the GATT subscribe with "Insufficient Authentication", which bleak raised as a bare
BleakGATTProtocolError — escaping connect() as an unhandled traceback.
Translate that (and related "Insufficient Encryption"/"not paired" rejections) into
a clean DeviceCommandError that names the fix: pass --ble-pin, and pair once in the
OS Bluetooth settings on Windows. It's classified as its own actionable case, never
as a dropped link, so the session offers a PIN rather than a pointless reconnect.
The startup probe now lets this actionable error through instead of collapsing every
failure to a bare "didn't answer", so the picker shows the real remedy in the splash.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Jean-Pierre MartineauandClaude Opus 4.8
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