LND

lnrpc: remove deprecated Send* RPC server implementations

Remove handler implementations and macaroon permission entries for the
now-deleted lnrpc RPCs: SendPayment, SendPaymentSync, SendToRoute, and
SendToRouteSync.

Also remove the dead payment infrastructure that was exclusively used by
these handlers: paymentStream, rpcPaymentRequest, rpcPaymentIntent,
extractPaymentIntent, dispatchPaymentIntent, sendPayment, and
sendPaymentSync.

routerrpc: remove deprecated SendPayment, SendToRoute, TrackPayment impls

Remove the SendPayment, SendToRoute, and TrackPayment shim methods from
router_server_deprecated.go that delegated to their V2 counterparts.
Remove their macaroon permission entries from router_server.go and the
now-unused legacyTrackPaymentServer wrapper.

routerrpc: remove deprecated outgoing_chan_id field handling

Remove the compatibility fallback in QueryRoutes and ExtractPaymentIntent
that accepted the deprecated single outgoing_chan_id field alongside the
replacement outgoing_chan_ids. Callers must now use outgoing_chan_ids.

Update TestQueryRoutes and TestExtractPaymentIntent accordingly.

itest: migrate deprecated lnrpc Send* calls to routerrpc V2

Remove SendToRoute and SendToRouteSync helpers from the test harness and
update integration tests to use routerrpc.SendToRouteV2:

- lnd_routing_test.go: collapse three SendToRoute test cases (sync,
stream, v2) into a single test using SendToRouteV2; update
testSendToRouteErrorPropagation to assert on Failure.Code instead of
PaymentError string
- lnd_channel_policy_test.go: replace streaming SendToRoute with
SendToRouteV2 and assert on HTLCAttempt.Failure instead of
PaymentError string

itest: add outgoing_chan_ids tests for EstimateRouteFee

routerrpc: add outgoing_chan_ids to EstimateRouteFee

cmd: add outgoing_chan_id flag to estimatefee

docs: add release note for coop close limbo fix

chancloser: remove dead ChannelFlushed.FreshFlush field

FreshFlush is never read in any transition handler. The only
producer (peer/brontide.go) sets it unconditionally to true,
and after the previous commit removed expectChanPendingClose,
the test loops that iterated over {true, false} no longer
differentiate between the two values.

Remove the field, the unconditional assignment, and collapse
the test loops into single sub-tests.

chancloser: add nil-tx guard to legacy close test

Add call tracking to the legacy mockChannel so that every
MarkCoopBroadcasted invocation is recorded. TestTaprootFastClose
now asserts that at least one call was made and that every call
carried a non-nil tx, guarding against the limbo state described
in https://github.com/lightninglabs/taproot-assets/issues/2108.

chancloser: remove MarkCoopBroadcasted(nil) calls

Remove the two call sites that set ChanStatusCoopBroadcasted
before a cooperative close transaction exists:

- BeginNegotiation in the legacy close path (chancloser.go)
- ChannelFlushed handling in the RBF close path
(rbf_coop_transitions.go)

Both calls passed nil as the close tx, creating a "limbo" state
where ChanStatusCoopBroadcasted is set but no close transaction
is stored. This is unnecessary because ShutdownInfo — persisted
earlier by MarkShutdownSent in initChanShutdown / the RBF
ShutdownPending transition — already serves as the durable
signal that the shutdown flow was entered.

ChanStatusCoopBroadcasted should only be set when a real close
transaction exists, which this change preserves.

kvdb: bump pgx/v4/stdlib to pgx/v5/stdlib

Update the SQL driver registration import from pgx/v4/stdlib to
pgx/v5/stdlib, completing the migration of the kvdb module away from
the deprecated pgx v4.

go.mod: add temporary replace directive for kvdb

Add a local replace directive for kvdb so the main module can reference
the local kvdb changes (pgx/v5 migration) before a new kvdb version is
released.

lnd: bump pgx/v4 to pgx/v5 in main module

Update the main module's pgxpool usage from pgx/v4 to pgx/v5:
- Change import from pgx/v4/pgxpool to pgx/v5/pgxpool
- Update pgxpool.Connect to pgxpool.New (v5 API change)
- Remove pgx/v4 and its transitive dependencies from go.mod

Note: pgxpool.New is lazy, but this is done in tests only and the very next
line is pool.Exec, so if there is a connection error, it will be caught there.

sqldb: use pgx/v5/pgconn instead of standalone pgconn

In pgx v5, the pgconn package was absorbed into the main pgx module.
Update imports from github.com/jackc/pgconn to
github.com/jackc/pgx/v5/pgconn and remove the now-unnecessary
standalone pgconn dependency from go.mod.

sqldb/v2: use pgx/v5/pgconn instead of standalone pgconn

In pgx v5, the pgconn package was absorbed into the main pgx module.
Update imports from github.com/jackc/pgconn to
github.com/jackc/pgx/v5/pgconn and remove the now-unnecessary
standalone pgconn dependency from go.mod.

docs: note bitcoind peer-check RPC switch

Document that bitcoind outbound peer health checks now use
getnetworkinfo.connections_out instead of getpeerinfo.

Also mention that texts of zmq port mismatch warnings were fixed.

chainreg: use typed getzmqnotifications RPC

Simplify the code. Use rpcclient's GetZmqNotifications method instead of a raw
request and manual unmarshalling when validating bitcoind ZMQ subscriptions.
The typed result already parses notification addresses, so the extra per-entry
URL parsing is removed.

chainreg: clarify zmq port-mismatch warnings

The previous warning text ("unable to subscribe to zmq ... events") suggested
that lnd failed to create the ZMQ connection, when in reality it only means the
configured port differs from what bitcoind reports via getzmqnotifications.
Reword both messages to say "port mismatch" and tell to verify the port.

Fixes https://github.com/lightningnetwork/lnd/issues/10568

chainreg: use getnetworkinfo for peer-count

Use getnetworkinfo.connections_out for bitcoind outbound peer checks instead
of getpeerinfo. This keeps the isolation-safety signal while avoiding heavier
per-peer work.

This helper is bitcoind-specific, btcd does not currently implement it.

chainreg: use GetNetworkInfo for version check

Simplify the code. Use rpcclient's typed GetNetworkInfo call in
getBitcoindHealthCheckCmd instead of a raw JSON-RPC request and
manual JSON decoding.

docs: add v0.21.0 RC testing guides for humans and agents

Adds docs/testing-guides/v0.21.0/ with a per-feature guide for the
v0.21.0-beta.rc1 release. Each guide follows a fixed template
(prereqs, setup, scenarios with concrete pass/fail signals, failure
investigation) so RC testers and automated agents can work through
them predictably.

Coverage:
- Headline features: production taproot channels, RBF taproot
coop-close, payment store KV->SQL migration, onion messaging +
rate limiting.
- High-risk regressions / breaking changes: closed-channel
tombstone (sqlite/postgres downgrade trap), reorg-safe channel
closes + MinCLTVDelta raise, chain_params network-mismatch DB
guard, GetDebugInfo log opt-in.
- New RPCs / operator features: payment-adjacent RPCs bundle,
multiple read-only middleware interceptors.

This is a first draft intended for community review on the PR.
payment-sql-migration.md carries a TBD callout for the
SkipNativeSQLMigration rescue-path behavior, pending developer
confirmation.

autopilot: pass pubkey in channel traversal

ForEachNodesChannels is a topology traversal: its callers only need
the node identity plus channel edges. After removing address loading
from ForEachNodeCached, constructing a Node for this callback is
misleading because Addrs is either unused or empty.

Pass NodeID directly through the interface and update the scoring
and simple graph callers to use that pubkey. This keeps the
address-bearing Node interface on ForEachNode, where autopilot
gathers connectable candidates and their addresses before dialing.

docs: add release note for autopilot graph-cache fix

Note the performance improvement from dropping the unnecessary address
load on the SQL backend and letting the kvdb in-memory graph cache
serve autopilot's scoring traversal.

mod: bump neutrino dependency