Add RegulatedConfidentialNoteFungibleToken preset

🧐 Motivation

The pieces are only useful together, and getting the wiring wrong silently breaks the compliance properties. A regulated deployment needs one reviewed composition it can deploy as-is.

📝 Details

contracts/src/token/presets/RegulatedConfidentialNoteFungibleToken.compact

• Wires core + Issuer + Authority + Audit + Delivery + supply, binding every role key in initialize.
• The whole design hangs off one chokepoint, emitOutput(ownerPk, encPk, value, slot): audit first (which produces the nonce), deliver second, commit third. Every output note the preset ever creates — mint output, transfer output, transfer change, burn change, seizure recovery — flows through it, which is what makes the compliance properties structural.
• Escrow-free seize (k=17, ~75k rows): owner-spend and seizure race on the same shared nullifier, so the authority never holds spend keys and no escrow account exists.
• Re-exports the ledger fields wallets, auditors, and indexers must read (a prefix-only import would keep them out of the generated ledger() reader).
• Costs: transfer k=18 / ~136k rows, burn k=17 / ~83k rows, mint k=17 / ~69k rows, attestSupply k=13 / ~4.7k rows.

Landed in #679 (draft).

Read contracts/src/token/presets/RegulatedConfidentialNoteFungibleToken.compact and the draft work in #679 first. Trace emitOutput and initialize, then verify that the listed token operations use the reviewed composition and that the required ledger fields are re-exported.