[Dijkstra] UTXOS: implement batch-level validity (POV, fee rules, collateral-on-failure)

[williamdemeo]

Tasks

• Define batch consumed/produced as sums across top-level and all subTxs.
• Fee rule: fee exists only at top level (subTx fee absent).
• Collateral rule: only top-level provides collateral; on any script failure, collect collateral and apply no other effects.

Acceptance criteria

• New code type-checks.
• Spec reflects "commit change of ledger state only on batch success."
• Integrates with script-validation pipeline from Issue [Dijkstra] batch-aware collectP2ScriptsWithContext + single evalP2Scripts at end #1006.