LND

docs: add release note

lnrpc: add XFindBaseLocalChanAlias rpc

Add the new RPC method that looks up the base scid for a given alias.
Given the previous stepping stones this commit is fairly simple, we just
call into the alias manager and return the lookup result.

multi: add base lookup option to AddLocalAlias

We add an extra option to the AddLocalAlias method which only controls
whether we store a reverse lookup from the alias back to the base scid
it corresponds to. The previous flag "gossip" is still maintained, and
in a way supercedes the new flag (it will also store the base scid
lookup even if the base lookup flag isn't set). The only call that sets
this option is the XAddLocalChanAlias RPC endpoint, where we want to
make sure that a reverse lookup is stored in the alias manager in order
to later expose it via the new RPC method.

lnd: update docs on nodeann addresses retaining

brontide: add new maxMessageSize variable

brontide+peer: use internal sync/pool to reduce allocations

This ensures that under medium to high load, we eliminate all
allocations once we arrive a steady state, re working memory.

docs: add docs explaining usage of pprof+benchmarks to optimize

In this commit, we add some docs that explain how to use tools like
heap escape analysis and memory profiling to fully eliminate allocations
in a sample program.

This guide is meant to help devs/contributors use Go's excellent perf
tools to zoom in on an optimization problem.

brontide: use a static buffer for the packet length

In this commit, we eliminate the final allocation that takes place when
we write out messages. Once again this was escaping to the heap, so we
make it an attribute on the Machine struct, which allows pure static
allocation.

```
goos: darwin
goarch: arm64
pkg: github.com/lightningnetwork/lnd/brontide
cpu: Apple M4 Max
BenchmarkWriteMessage-16 25840 46376 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25646 46672 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25874 46391 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25512 46427 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25760 46309 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25789 46520 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25602 46619 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25766 46464 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25820 46487 ns/op 2 B/op 0 allocs/op
BenchmarkWriteMessage-16 25634 46553 ns/op 2 B/op 0 allocs/op
PASS
ok github.com/lightningnetwork/lnd/brontide 16.907s
```

brontide: use a fixed size buffer for the nonce within the brontide machine

In this commit, we use a fixed sized buffer for the nonce when we
read/write messages. This was actually escaping to the heap. We can
avoid this by statically allocating it alongside the struct itself.

The benchmark state at this point:

```
goos: darwin
goarch: arm64
pkg: github.com/lightningnetwork/lnd/brontide
cpu: Apple M4 Max
BenchmarkWriteMessage-16 25264 47012 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 23542 46809 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 25989 47256 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 25542 46388 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 26083 46612 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 25860 46367 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 24967 46748 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 26088 46485 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 25561 46425 ns/op 4 B/op 1 allocs/op
BenchmarkWriteMessage-16 25474 47249 ns/op 4 B/op 1 allocs/op
PASS
ok github.com/lightningnetwork/lnd/brontide 16.911s
```

```
goos: darwin
goarch: arm64
pkg: github.com/lightningnetwork/lnd/brontide
cpu: Apple M4 Max
│ old.txt │ new2.txt │
│ sec/op │ sec/op vs base │
WriteMessage-16 50.34µ ± 1% 46.68µ ± 1% -7.28% (p=0.000 n=10)

│ old.txt │ new2.txt │
│ B/op │ B/op vs base │
WriteMessage-16 73788.000 ± 0% 4.000 ± 0% -99.99% (p=0.000 n=10)

│ old.txt │ new2.txt │
│ allocs/op │ allocs/op vs base │
WriteMessage-16 5.000 ± 0% 1.000 ± 0% -80.00% (p=0.000 n=10)
```

brontide: add benchark for WriteMessage

In this commit, we add a benchmark for the WriteMessage method. This is
the first step in an upcoming optimizooor series of commits.

The baseline is:
```
goos: darwin
goarch: arm64
pkg: github.com/lightningnetwork/lnd/brontide
cpu: Apple M4 Max
BenchmarkWriteMessage-16 22736 50667 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 23217 50463 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 24241 49941 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 23574 51021 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 23784 49926 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 24230 50538 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 24058 49971 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 23762 50224 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 24266 53034 ns/op 73788 B/op 5 allocs/op
BenchmarkWriteMessage-16 23317 50045 ns/op 73788 B/op 5 allocs/op
PASS
ok github.com/lightningnetwork/lnd/brontide 17.433s
```

lnd: use persisted addrs if not set in config

lnd: stop using prev persisted addresses

In this commit we stop using persisted address in LND's prev run.
This means addresses set using `externalip` will be used without
merging them with the ones from prev run. We will introduce the
condition to use persisted addresses in the next commit.

itest: check for config addrs precedence

In this commit, we update the itest to check for precedence of the
config addresses over the persisted addresses.

We did not check for address persistence after restart (without the
extraArgs `--externalip`) because in `lntest/node/config.goL300`,
`GenArg` by default sets the `--externalip` flag, which makes
the config addrs to always take precedence over the persisted
addrs, for the tests.

docs: add release note

funding: notify aux negotiator on ChannelReady

We notify the aux channel negotiator that an established channel is now
ready to use.

lnwallet: include peer pub key in aux chan state

In order to help external components to query the custom records of a
channel we need to expose the remote peer pub key. We could look-up
custom records based on the funding outpoint, but that relation is
established when receiving the ChannelReady message. The external
components may query the AuxChanState before that message is received,
so let's make sure the peer pub key is also available.

lnwire: update tests for init message

htlcswitch+peer: set and read aux custom records

This is the final step, we actually call the interface and either
provide or retrieve the custom features over the message. We also notify
the aux components when channel reestablish is received.

lnwire: add custom records to init

Before calling the new interface we first add the ability for the peer
message itself to encode the new data records.

lnd: add AuxChannelNegotiator to AuxComponents

We now plug-in the aux channel negotiator to the server impl config. We
also provide it to the peer config as that's where it's needed in order
to inject custom records in the appropriate peer messages.

lnwallet: introduce AuxChannelNegotiator interface

We introduce this new interface with the purpose of injecting and
handling custom records on the init message, and also notifying
external components when receiving the ChannelReady or
ChannelReestablish message.

github: change to form-based issue template

This commit introduces a more structured approach to issue generation,
where we can make certain info required.

rpcserver+itest: skip err from `FlapCount`

We need to make sure the `ListPeers` to be robust against errors from
the `FlapCount` so this RPC won't fail due to no flap count info. Also
updated the itest to check this field.

docs: update release notes

lntest+rpcserver: ignore `chanfitness.ErrPeerNotFound` in rpc

Similar to how we handle `chanfitness.ErrChannelNotFound`, we now also
ignore the `ErrPeerNotFound`. This is needed as previously we will
always see the peer in the channel event store given it'd added when
connected. This is no longer the case as we only add the peer to the map
when the channel is added.