docs: commit the new-driver checklist, step 2 rewritten for packages

The checklist (with the Intel UHD 750 worked example) existed only as
an untracked file in the main checkout — the plan referenced it but no
branch could see it. It lands here with its build step rewritten
against the finished package template: create the driver's own
build.zig/zon from the pci-bus template, then one dependency + one
boot-tree row + one zon line in the root build. devices-csv.md's
adding-a-driver section and the plan's checklist references point at
it again.

docs/build-packages-plan.md

@@ -113,9 +113,9 @@ images, release ISO, check steps) and `build/qemu.zig` (the run steps + OVMF
 probing), imported by a short root `build.zig`.
 
 **Afterwards** (outside this plan): the intel-uhd-graphics-750 driver is
-(re)created as a greenfield package — the "Adding a driver" checklist's build
-step (docs/device-driver-development/devices-csv.md, step 1) gets rewritten
-against the package template at that point.
+(re)created as a greenfield package. The new-driver checklist's build step
+(docs/device-driver-development/new-driver-checklist.md, step 2) is already
+rewritten against the package template.
 
 ## Execution notes (the finished shape)
 
@@ -159,6 +159,7 @@ style: no Co-Authored-By trailers.
   struct sizes) — they moved into their binaries' packages with their waves,
   discharging the carry-along obligation.
 - Doc updates ride each phase: docs/README.md (repo layout + source map),
-  docs/device-driver-development/devices-csv.md ("Adding a driver", step 1),
-  and the docs that cite the build recipe (driver-model.md, threading.md,
-  system-requirements.md) reference build shapes that keep changing.
+  docs/device-driver-development/new-driver-checklist.md (step 2) and
+  devices-csv.md ("Adding a driver"), and the docs that cite the build recipe
+  (driver-model.md, threading.md, system-requirements.md) reference build
+  shapes that keep changing.