v2.12.2

## Changelog

Refer to the [2.12 Upgrade Guide](https://docs.nats.io/release-notes/whats_new/whats_new_212) for backwards compatibility notes with 2.11.x.

### Go Version

- 1.25.4 (#7520)

### Dependencies

- github.com/klauspost/compress v1.18.1 (#7474)
- github.com/nats-io/nats.go v1.47.0 (#7474)
- golang.org/x/sys v0.38.0 (#7538)
- github.com/minio/highwayhash 070ab1a (#7539)

### Added

General

- Support for the PROXY protocol (v1 and v2) for client connections, when `proxy_protocol: true` is set in the config (#7456)

JetStream

- Added `meta_compact` and `meta_compact_size`, advanced JetStream config options to control how many log entries must be present in the metalayer log before snapshotting and compaction takes place (#7484, #7521)
- Added `write_timeout` option for clients, routes, gateways and leafnodes which controls the behaviour on reaching the `write_deadline`, values can be `default`, `retry` or `close` (#7513)

Monitoring

- Added expvar `/debug/vars` endpoint to the monitoring port (#7469)
- Meta cluster snapshot statistics have been added to the `/jsz` endpoint (#7524)
- The `/jsz` endpoint can now show direct consumers with the `direct-consumers?true` flag (#7543)

### Improved

General

- Binary stream snapshots are now preferred by default for nodes on new route connections (#7479)
- Reduced allocations in the sublist and subject transforms (#7519)

JetStream

- Improved the logging for observer mode (#7433)
- Improve interest detection when consumers are created or deleted across different servers (#7440)
- Improved the performance of enforcing `max_bytes` and `max_msgs` limits (#7455)
- Streams and consumers will no longer unnecessarily snapshot when being removed or scaling down (#7495)
- Streams are now loaded in parallel when enabling JetStream, often reducing the time it takes to start up the server (#7482, #7526)
- Log lines and errors related to offline/unsupported assets are now clearer (#7416, #7425)
- Stream catchups will now use delete ranges more aggressively, speeding up catchups of large streams with many interior deletes (#7512)
- Streams with subject transforms can now implicitly republish based on those transforms by configuring `>` for both republish source and destination (#7515)
- A race condition where subscriptions may not be set up before catchup requests are sent after a leader change has been fixed (#7518)
- Reduced heap allocations in hash checks (#7539)
- Healthchecks now correctly report when streams are catching up, instead of showing them as unhealthy (#7535)
- Potentially reduced the number of calls to the account resolver for assets that are not resident on that server (#7537)

### Fixed

General

- When using message tracing, header corruption when setting the hop header has been fixed (#7443)
- Fixed a bug when validating leafnode proxies (#7444)
- Fixed a regression where token authentication would not be parsed correctly in leafnode URLs (#7452)
- Gateway subscribe/unsubscribe will no longer block on account fetches (#7449) 
- Shutting down a server using lame-duck mode should no longer result in max connection exceeded errors (#7527)

JetStream

- Caches will now no longer expire unnecessarily when re-reading the same sequences multiple times in first-matching code paths (#7435)
- Fixed a bug in atomic batching where the incorrect field would be checked when looking for unsupported headers (#7436)
- Fixed a deadlock that could happen when interleaving a direct get request with a batch write (#7458)
- A couple of issues related to header handling have been fixed (#7465)
- No-wait requests now return a 400 No Messages response correctly if the stream is empty (#7466)
- Raft groups will now only report leadership status after a no-op entry on recovery (#7460)
- Fixed a race condition in the filestore that could happen between storing messages and shutting down (#7496)
- A panic that could occur when recovering streams in parallel has been fixed (#7503)
- An off-by-one when detecting holes at the end of a filestore block has been fixed (#7508)
- Indexing a message block in the filestore no longer tries to adjust the cache first sequence (#7508)
- Writing skip message records in the filestore no longer releases and reacquires the lock unnecessarily (#7508)
- Writing message records only overwrites the cache first sequence on the first indexed write (#7508)
- Fixed a bug on metalayer recovery where stream and consumer monitor goroutines for recreated assets would run with the wrong Raft group (#7510)
- Scaling up an asset from R1 now results in an installed snapshot, allowing recovery after restart if interrupted, avoiding a potential desync (#7509)
- Raft groups should no longer report no quorum incorrectly when shutting down (#7522)
- Consumers that existed in a metalayer snapshot but were deleted on recovery will no longer result in failing healthchecks (#7523)
- An off-by-one when detecting holes at the end of a filestore block has been fixed (#7525)
- Fixed a race condition that could happen with shutdown signals when shutting down JetStream (#7536)
- Fixed an issue in the filestore where skipping message sequences did not correctly update the cache accounting (#7534)
- Fixed a deadlock that could occur when purging a stream with mismatched consumer state (#7546)

### Complete Changes
 
https://github.com/nats-io/nats-server/compare/v2.12.1...v2.12.2