capability

Live capability of the fabric carrying this session — its role(s) and whether it is usable right now. Updates as radios, permissions, and network paths change.

Default: a roleless FabricAvailability.Unknown floor — a fabric with no live path observer reports "cannot tell", never a confident Available. Fabrics with real OS observers override this to make it reactive; a fabric that does so declares reportsLiveCapability = true in its SeamCapabilities.