[Core] Timeline for supporting Boost >= 1.87?

Description

Ray pins Boost 1.81.0 (December 2022), via com_github_nelhage_rules_boost @ 57c9939 in bazel/ray_deps_setup.bzl. Boost 1.87.0 (2024-12-12) removed Asio's deprecated compatibility surface, and the current release is 1.91.0 (2026-04-22).

Ray master still uses boost::asio::io_service, resolver::query, resolver::iterator and basic_waitable_timer::expires_from_now — in src/ray/raylet/worker_pool.h, src/ray/util/network_util.cc, src/ray/gcs/store_client/redis_context.cc and src/ray/object_manager/plasma/get_request_queue.cc — so the tree does not compile against any Boost >= 1.87. (#51866 removed most io_service usage; that is what remains. #50039 was closed as stale.)

1. Is a Boost upgrade on the roadmap — which version, and roughly when?
2. If it is not scheduled, would you take a PR porting those call sites to the modern spellings first? It is a no-op against the vendored 1.81 and makes the tree 1.87+-clean whenever the pin does move.

Use case

We build every dependency from source into one HPC image against a single Boost (1.91), so we carry local patches to Ray's Asio call sites just to compile it, and would like to drop them.

Start with bazel/ray_deps_setup.bzl to confirm the pinned Boost version, then inspect the listed Asio call sites in src/ray/raylet/worker_pool.h, src/ray/util/network_util.cc, src/ray/gcs/store_client/redis_context.cc, and src/ray/object_manager/plasma/get_request_queue.cc. Verify the affected code builds with the current pin and with Boost 1.87 or newer; done means the remaining deprecated Asio usages no longer block the upgrade.