Persistent GUID for this iframe instance, assigned by the runtime. Survives page reloads.
How session identity was established (RENAME-01, v1.8 Phase 42).
'nip-5d' = identity registered at iframe creation via originRegistry (canonical NIP-5D path).
'legacy-auth' = legacy AUTH handshake (pubkey is the derived keypair pubkey).
Renamed from identitySource: 'auth' | 'source' in v1.8; see .changeset/v1-8-rename-01-session-provenance.md.
Registry entry mapping a napplet's windowId to its runtime metadata. Created after a successful identity establishment (AUTH handshake or NIP-5D origin registration).