Merge pull request #65394 from athanatos/sjust/wip-seastore-cleanups-2025-08

seastore: misc cleanups, coroutine conversions

Reviewed-by: Matan Breizman <mbreizma@redhat.com>

diff --cc src/crimson/os/seastore/cache.cc
Simple merge

diff --cc src/crimson/os/seastore/extent_placement_manager.cc
Simple merge

diff --cc src/crimson/os/seastore/seastore.cc
Simple merge

diff --cc src/crimson/os/seastore/seastore.h
Simple merge