[$] The beginning of the 6.13 merge window

As of this writing, just over 1,800 non-merge changesets have been pulled
into the mainline kernel for the 6.13 release. That number may seem small,
given that a typical merge window brings in at least 12,000 commits, but
the early pulls this time around have focused on significant core changes,
and there are quite a few of them. The time has come to summarize the
changes pulled so far, including lazy preemption, multi-grained timestamps,
new extended-attribute system calls, and more.