LND

chanstate: move taproot channel helpers

Move the backend-neutral taproot shachain and verification nonce
helpers into chanstate with the thaw-height threshold they support.

Leave channeldb aliases for existing callers while OpenChannel and its
receiver methods are moved across the package boundary.

channeldb: add store status check

Add a transitional non-locking status predicate for channeldb store
code and use it from KV serialization helpers.

This avoids calling an unexported OpenChannel helper from channeldb
after the type moves into chanstate.

chanstate: move open channel type

Move OpenChannel and its backend-neutral receiver methods into the
chanstate package.

channeldb now keeps a compatibility alias while retaining the KV store
implementation and serialization helpers. Tests that used private
channel status fields now use store-facing accessors.

channeldb: derive channel packagers

Remove the KV forwarding packager from OpenChannel and derive a
ChannelPackager inside the channeldb store methods that need one.

This keeps the backend-specific kvdb transaction helper in channeldb,
so the OpenChannel type no longer carries that dependency toward
chanstate.

chanstate: move revocation log types

Move the revocation-log value types and TLV serialization helpers into
chanstate.

Leave channeldb aliases and wrapper functions for the existing KV
persistence code and tests. Bucket keys, errors, and transaction
helpers stay in channeldb, so this commit only moves backend-neutral
state data.

chanstate: add previous state lookup

Add FindPreviousState to the chanstate commitment store subinterface now that
RevocationLog is a chanstate value type.

This extends the store contract without changing runtime behavior. The
existing ChannelStateDB method already satisfies the new method.

channeldb: move revocation tail helper

Keep the revocation-log tail-height helper on ChannelStateDB instead of
the OpenChannel receiver.

The helper is only used by channeldb tests, so it should not become
part of the backend-independent chanstate store contract. The tests now
call the concrete helper directly.

channeldb: store channel state by interface

Change OpenChannel.Db to the composed chanstate Store interface while
keeping the existing field name.

Tests that need raw channeldb access now assert the concrete test
backend explicitly instead of reaching through OpenChannel.Db. This
keeps backend setup out of the store contract.

channeldb: split out channel kv helpers

Convert the KV-only OpenChannel helpers for TLV aux data and
borked-state lookup into package-level channeldb helpers.

This keeps serialization and bucket inspection code tied to the KV
backend while leaving the OpenChannel receiver set closer to the future
chanstate type.

channeldb: add channel store accessors

Add transitional OpenChannel accessors for the channel status and
confirmed SCID fields used by KV store code.

These helpers keep the fields private while allowing channeldb backend
code to continue hydrating and serializing channel state after
OpenChannel moves to chanstate.

chanstate: add commit tail store

Add the commitment-tail advancement method to the chanstate commitment
store subinterface.

Move the existing AdvanceCommitChainTail KV transaction body onto
ChannelStateDB. The OpenChannel receiver now keeps locking and restored
channel checks before delegating persistence through the store.

chanstate: add forwarding package store

Add a forwarding-package store subinterface to chanstate.Store.

Move the existing OpenChannel forwarding-package KV transaction bodies
onto ChannelStateDB. The OpenChannel receivers keep their locking
behavior and delegate package loading, acking, filtering, and removal
through the store.

channeldb: move revocation log reads

Move the remaining OpenChannel revocation-log KV reads onto
ChannelStateDB.

This keeps FindPreviousState and the unit-test tail-height helper as
OpenChannel wrappers. It removes direct backend access from the
receiver methods while leaving RevocationLog in channeldb for now.

chanstate: move forwarding package types

Move FwdState, PkgFilter, and FwdPkg into chanstate with their existing
comments and helper methods.

Leave channeldb aliases for the moved value types and constructors so
current callers keep compiling. The KV forwarding package persistence
code stays in channeldb.

chanstate: add commitment read stores

Add commitment-height, latest-commitment, and remote revocation store
lookups to the chanstate commitment store subinterface.

Move the existing OpenChannel KV view transaction bodies onto
ChannelStateDB. This leaves the receivers as store-call wrappers while
keeping the persisted format and read behavior unchanged.

chanstate: add commitment store subinterface

Add a commitment-focused store subinterface for updating local channel
commitment state. This lets OpenChannel call through the chanstate
store contract instead of reaching directly into the KV backend.

Keep the existing KV transaction body on ChannelStateDB for now. The
receiver still owns locking and in-memory state updates while the store
method owns persistence.

chanstate: move commitment diff types

Move CommitDiff and its forwarding reference types into chanstate. This
lets the next commitment store subinterface name pending remote commitment
state without importing channeldb.

Keep forwarding package persistence and commit-diff serialization in
channeldb for now. The aliases preserve existing call sites while the
KV backend code remains in place.

chanstate: add remote commit chain store

Add the remote commitment-chain append method to the chanstate
commitment store subinterface.

Move the existing KV transaction body onto ChannelStateDB and have the
OpenChannel receiver call through the store. This removes another
direct backend dependency from OpenChannel while keeping KV persistence
code in channeldb.

chanstate: add commit lookup store

Add read-side commitment lookup methods to the chanstate commitment
store subinterface.

Move the existing OpenChannel KV view transaction bodies onto
ChannelStateDB. Leave the OpenChannel receivers as store-call wrappers.
This removes three more direct backend references from the receiver
code without changing the persisted data format.

chanstate: add revocation insert store

Add the next-revocation persistence method to the chanstate commitment
store subinterface.

Move the existing OpenChannel KV update body onto ChannelStateDB. The
OpenChannel receiver keeps the external locking behavior and delegates
persistence through the store interface.

chanstate: move log update type

Move LogUpdate into chanstate so commitment store interfaces can refer
to pending update state without importing channeldb.

Keep the log-update serialization helpers in channeldb. Those helpers
remain part of the existing KV disk format and can move with the KV
backend implementation later.

chanstate: add open channel status store

Add a status subinterface to the chanstate Store contract for status bit
updates and data-loss commit point handling. Implement the subinterface on
ChannelStateDB using the existing persistence code.

Update the matching OpenChannel receivers to call through the store
methods. The broadcast path still uses a private channeldb helper until
its closing-transaction subinterface is introduced in a later commit.

chanstate: add open channel close stores

Add shutdown and close-transaction subinterfaces to the chanstate Store
contract. These cover persisted shutdown info plus stored unilateral
and cooperative closing transactions.

Implement the subinterfaces on ChannelStateDB with the existing KV code and
update OpenChannel receivers to call through the store methods. The
backend-specific key selection remains private to channeldb.

chanstate: add pending channel setup store

Add pending-channel setup to the chanstate lifecycle store subinterface. This
covers the path that writes a new pending channel and records the
funding broadcast height.

Move the OpenChannel receiver to call through ChannelStateDB and pass
the backend explicitly into the channeldb sync helper. This keeps the
link-node persistence detail in channeldb while removing another direct
backend reference from OpenChannel.

chanstate: move shutdown metadata

Move the ShutdownInfo state type, constructor, and closer helper into
chanstate. The type describes channel shutdown state and is not tied to
the concrete KV backend.

Keep the TLV encode and decode helpers in channeldb for now, since
those functions describe the current persisted format. The channeldb
constructor remains as a compatibility wrapper.