fromRawEvent
Converts RawLedgerEvent to DustEvent.
Note: Since we can't easily discriminate event types without full SCALE decoding, we create a generic DustSpendProcessed event and let DustLocalState.replayEvents() handle the actual type checking.
In production, this should:
Decode SCALE event discriminant
Match to specific DustEvent subtype
Return appropriate variant
Return
DustEvent (currently always DustSpendProcessed as placeholder)
Parameters
rawEvent
Raw ledger event