commucat-ledger

Lightweight adapters for exporting CommuCat audit digests.

• NullLedger – no-op sink used in tests and local development.
• FileLedgerAdapter – appends newline-delimited JSON to a file, creating parent directories when necessary.
• DebugLedgerAdapter – emits digests via tracing (target commucat::ledger).

The server and CLI use these adapters to record device key rotations, session events and other audit trails.