Cardano publish block coercion

[nicolasLuduena]

This pull request refines the lowering process for Cardano block publishing by introducing more context-aware transformations for specific fields. The main improvement is that each field (To, Amount, and Datum) now uses a specialized context when being lowered, which should help ensure correctness and clarity in how these fields are processed.

Enhancements to context handling during lowering:

• The To field now uses ctx.enter_address_expr() to provide an address-specific context before lowering.
• The Amount field now uses ctx.enter_asset_expr() to provide an asset-specific context before lowering.
• The Datum field now uses ctx.enter_datum_expr() to provide a datum-specific context before lowering.