multi: implement awareness of the final/production taproot channel variant

[Roasbeef]

This pull request implements comprehensive support for production taproot channels in LND, introducing the ability to create and manage channels using the finalized taproot specification with optimized script structures. Production taproot channels utilize feature bits 80/81, and utilize resolution scripts that have been optimized using miniscript.

This PR builds on top of https://github.com/lightningnetwork/lnd/pull/9982 which adds some prepatory TLVs to support splicing in the future.

In aggregate, these changes are intended to implement the final set of upcoming changes to the taproot chans spec.

Implementation Overview

Core Infrastructure

The implementation introduces a comprehensive witness type system that distinguishes between staging and production taproot channels. Seven new "Final" witness types have been added to handle all taproot channel operations including commitment spends, HTLC resolution, and revocation scenarios.

A new channel type bit TaprootFinalBit has been added to the channel database infrastructure, allowing the system to persistently track whether a channel uses production or staging taproot scripts.

Contract Resolution System

The contract court system has been extensively updated to support production taproot channels throughout the resolution process. All HTLC resolvers now accept channel type information and use it to select appropriate witness types during contract resolution. The UTXO nursery has been integrated to properly handle time-locked outputs from production taproot channels.

The witness type selection follows a consistent three-way pattern throughout the codebase: production taproot channels use Final witness types, staging taproot channels use existing taproot witness types, and legacy channels continue using their established witness types.

Script Generation and Wallet Integration

The wallet's commitment transaction generation logic has been updated to use appropriate script options based on the channel type. A new script option system allows callers to specify whether production or staging script variants should be generated, with the wallet automatically selecting the correct option based on the channel's type.

Script generation functions throughout the input package now accept TaprootScriptOpt parameters that enable production script generation when appropriate.

External Interfaces

The RPC interface has been extended with a new SIMPLE_TAPROOT_FINAL commitment type that allows external clients to explicitly request production taproot channels. The funding manager's negotiation logic has been updated to handle production taproot channel requests and ensure that both parties support the necessary feature bits before establishing the channel.

Backward Compatibility

This implementation maintains full backward compatibility with existing channel types. Staging taproot channels continue to function exactly as before, and legacy channels remain unaffected. The new production taproot functionality is additive and does not modify any existing behavior.

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TODO Checklist

• [ ] Add breach arbitrator support for production taproot channels
• [ ] Update integration test matrix to include production taproot scenarios
• [ ] Complete watchtower justice transaction support for production channels
• [ ] Update documentation with production taproot channel guidelines

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[Roasbeef]

Rebased on top of the updated dep PR.

[Roasbeef]

Added a final set of commits to add the new channel type to the relevant commitment type test matrices in the itests.

[Roasbeef]

Tacked on two additional commits to add the nonce map to revoke and ack.

[Roasbeef]

Pushed a commit to only set the new nonce map field based on the "final" feature bit.

[lightninglabs-deploy]

@yyforyongyu: review reminder @gijswijs: review reminder