Add driver-delivery (kld/kext/IOKit) sidebar under the monorepo plan

Provisional IOKit sidebar synthesizing 7 research passes + a read of the ~14
existing kext/IOKit plans and the ko2kext tooling. Verdict: three-tier form
policy (compiled-in / plain kld / kext where firmware or multi-version) and
NO IOKit C++ runtime -- already the shipped direction. Key refinement: only
~50-60 of the catalog's 343 kext candidates need kext treatment; the rest stay
plain klds on native devmatch. Firmware offline via firmware(9)/FreeBSD-15 raw
/boot/firmware; wired-memory win honestly tens of MB; nvidia coexistence is
on-disk/per-boot only; make extensions target formalizes ko2kext.

Linked nested under the monorepo plan entry in nextbsd-research; IOKit stays
flagged provisional.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: pkgdemon