Capture omarchy-air's post-10-16 customizations into its layer

Everything on the Air that existed only on the machine:

- git/config and mimeapps.list, which the omarchy-air-host branch captured
  but profiles never picked up.
- NetBird: netbird-bin under [aur], the networkd drop-in it writes, and a
  setup.sh that runs `netbird service install` and enables the unit (the AUR
  package ships none). `netbird up` stays manual.
- ufw rules beyond Omarchy's stock set and the handoff step's 4242 rule:
  ssh and the ocovo fabric (7746/udp) from the home LAN, 7746 over wt0, and
  7790/tcp.

base gains omarchy-fix-qt-color and a setup.sh that runs it. Qt 6.12's
QtQuick Color singleton shadows the shell's qs.Commons Color, so the bar,
lock screen and polkit dialog lose every colour; the fix renames the
singleton to ShellColor. An omarchy upgrade restores the stock files, so it
is idempotent, skips Qt < 6.12, and no-ops once upstream renames it.
Verified: run against the pristine backup it reproduces the Air's
hand-patched /usr/share/omarchy/shell byte for byte.

Left out on purpose: ocovo-node.service (written by `ocovo service
install`) and environment.d/ohv.conf belong to those projects.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

profiles/machines/macbook-air-m2/profile

@@ -2,6 +2,7 @@
 # Captured as it is on 2026-10-16 (Omarchy 4.0.3rc4): no hand-built themes, no
 # shell plugins, stock bar, stock terminal fonts. Add personal-desktop to
 # include= to give it the HP's desktop.
+# 2026-11-01: plus git/config, mimeapps.list, NetBird and ufw rules (setup.sh).
 description="MacBook Air M2 (omarchy-air): Asahi, aarch64"
 include=(base personal features/handoff roles/developer roles/devops roles/ai-agents)
 hostnames=(omarchy-air)