[Dijkstra] Document ENTITIES/SUBENTITIES

1. Precondition `∙ filter isKeyHash wdrlCreds ⊆ dom voteDelegs₀` is dropped from Conway (see [CIP-0181](https://github.com/cardano-foundation/CIPs/tree/master/CIP-0181), and issue [#5910](https://github.com/IntersectMBO/cardano-ledger/issues/5910))
2. Withdrawals from subtransactions are only allowed from pre-transaction registered accounts.
3. Aggregated withdrawals must no exceed the pre-transaction account balance. (see [phantom asset attack](https://github.com/cardano-foundation/CIPs/tree/master/CIP-0159#partial-withdrawals-and-native-asset-withdrawals))
4. Withdrawals are applied before CERTS and direct deposits after CERTS
5. In legacy mode, the top-level transaction can withdraw from an account registered (and deposited onto) by a subtransaction.
6. In legacy mode, the top-level transaction can only do a full withdrawal.

Locate the Dijkstra ENTITIES/SUBENTITIES material referenced by the issue and read the surrounding formal specification. Document the six listed withdrawal and registration rules, including the Conway changes and legacy-mode distinctions, with the linked CIP references preserved; done means each stated behavior is represented clearly.

Written by the indexing model from the issue text.