Simplicity covenant helpers & PSET builder

[ardier16]

Describe the feature

Description:
Port all Simplicity covenant integration code, transaction builders, and utilities for Jade signing.

Acceptance Criteria:

• Covenant source registry ported from web/src/simplicity/sources.ts and covenants/ folder:
  • p2pk.ts — P2PK program
  • lending.ts — lending covenant
  • asset_auth.ts — asset authorization
  • pre_lock.ts — pre-lock covenant
  • script_auth.ts — script hash verification
• preLockCovenants.ts ported — address derivation chain computation:
  • AssetAuth → Lending → ScriptAuth → PreLock chain
  • Script pubkey derivation for outputs
• PSET builder ported from web/src/tx/psetBuilder.ts:
  • Wrapper over LWK PsetBuilder
  • Input/output management
  • Asset issuance (entropy-based asset ID)
  • Script compilation from addresses
  • Fallback nLockTime for liquidation covenants
  • Txid byte order conversion (display ↔ internal)
• Utility helpers ported:
  • parametersEncoding.ts — NFT parameter encoding
  • addressP2pk.ts — P2PK address derivation
  • esploraPrevout.ts — prevout tx fetching
  • finalizeSimplicityInputs.ts — Simplicity input finalization
  • taprootUnspendableKey.ts — taproot key helpers
• All transaction builders ported:
  • preLockCreation/ — create pre-lock covenant
  • issueUtilityNfts/ — issue 4 utility NFTs
  • prepareUtilityNfts/ — prepare 4 utility UTXOs
  • acceptOffer/ — accept offer (build lending covenant input)
  • loanRepayment/ — repay loan
  • loanLiquidation/ — liquidate expired loan
  • preLockCancellation/ — cancel pending offer
• All TX types updated for Jade signing (no P2PK seed-based signing)
• Manual test: createP2trAddress(source, args, internalKey, testnet) output matches web/ for identical inputs

Notes:

• Transaction builders adapted for Jade PSET signing (remove seed-based signing)
• Keep covenant source compilation logic identical to web/
• All outputs should be testable against web/ equivalents