docs: document NVMe partition sizes and GPU output verification

Co-authored-by: aider (openrouter/openai/gpt-5.2) <aider@aider.chat>

docs/nixos_build_spec.md

@@ -10,13 +10,13 @@ Target disk: /dev/nvme0n1
 Install target is NVMe only. Do not select /dev/sdX devices in the installer.
 
 KEEP (do not format):
-- /dev/nvme0n1p1 (EFI vfat) UUID=94CC-9DA4
-- /dev/nvme0n1p2 (MS reserved)
-- /dev/nvme0n1p3 (Windows NTFS) UUID=8294CD2994CD2111
-- /dev/nvme0n1p4 (Windows recovery NTFS) UUID=6E1AA32B1AA2EEF1
+- /dev/nvme0n1p1 (EFI vfat) UUID=94CC-9DA4 (~99MiB, FAT32, mounted at /boot/efi)
+- /dev/nvme0n1p2 (MS reserved) (~15MiB)
+- /dev/nvme0n1p3 (Windows NTFS) UUID=8294CD2994CD2111 (~503GiB)
+- /dev/nvme0n1p4 (Windows recovery NTFS) UUID=6E1AA32B1AA2EEF1 (~529MiB)
 
 WIPE + install NixOS here:
-- /dev/nvme0n1p5 (currently Ubuntu ext4 /) UUID=4e99904c-ce6f-4c3c-898a-e29cfc373489
+- /dev/nvme0n1p5 (currently Ubuntu ext4 /) UUID=4e99904c-ce6f-4c3c-898a-e29cfc373489 (~449GiB)
 
 ## Other attached disks (DO NOT FORMAT)
 - /dev/sda (240GB) model: Patriot Burst El (KEEP)

niri-4screen.md

@@ -23,6 +23,14 @@ HARDWARE SUMMARY
 - Notes: There may be multiple /dev/dri/card* devices. Session must pick the
   correct device driving the 4 DP outputs.
 
+NOTE (2026-01 recon):
+- Current Ubuntu hardware scan shows NVIDIA Quadro P620 is driving /dev/fb0 at 1680x1050.
+- This suggests the monitors may actually be attached to the Quadro, not the Intel outputs.
+- Before finalizing GPU/device selection, verify:
+  - ls -l /dev/dri/by-path
+  - loginctl seat-status seat0
+  - (optional) niri output listing once in session
+
 KNOWN KERNEL / PLATFORM ISSUES
 - IOMMU faults / “Operation not permitted” style crashes were avoided on Ubuntu
   with kernel flags: