Cardano Updates

collect and organize all helper functions that return inhabitants of the
following types: ℙ TxIn, ℙ TxOut, ℙ Script, ℙ Datum

Co-authored-by: William DeMeo <[email protected]>

Update SECURITY.md

Co-authored-by: Facundo Domínguez <[email protected]>

Co-authored-by: Facundo Domínguez <[email protected]>

+  changed globalScripts type; fixed Transaction docs
+  revise doc prose in Utxo module
+  rebase fixes
+  rewrite premises of UTXO rule

   +  **No overlapping spends across subtransactions and top-level tx**: add explicit pairwise-disjointness premise for batch spending inputs.

   +  **Reference-script/self-usable-output concern**: move reference-input validation to batch output view so reference inputs may point to outputs from full batch (including its own outputs), while keeping spending inputs mempool-safe against utxo₀.

+  Remove contradiction between "ref inputs may refer to earlier tx outputs in the batch" vs "all inputs must exist before applying any tx in the batch." The new text punts the exact constraint to the UTxO rules (where it belongs).
+  Fix Plutus bullet (old "nor earlier versions" reads like "no Plutus at all").
+  Align fees with current Agda (`txFee : InTopLevel …`), but leave room for later CIP-driven updates.
+  Introduce subTx info type (using an alias for `TxInfo` for now).
+  Extend `TxInfo` with field `txInfoSubTxs : Maybe (List SubTxInfo)`.
+  Define a purpose-built builder:

   + Top-level Guard scripts ⇒ `txInfoSubTxs = just (...)`
   + Everything else ⇒ `txInfoSubTxs = nothing`
   + SubTx scripts ⇒ always `nothing` (even for `Guard` at sub level)
+ Explain two utxo arguments
+ Clean up txInfoForPurpose