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/base/setup.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# base setup, run by install.sh's `setup` step after the files are in place.
+# Idempotent; honours OMARCHY_SETUP_DRY=1.
+set -uo pipefail
+
+# Qt 6.12's QtQuick Color singleton blanks the bar (see bin/omarchy-fix-qt-color).
+# An omarchy upgrade restores the stock shell, so re-run install.sh's setup step,
+# or the script itself, after updating.
+fix=$OMARCHY_SETUP_LAYER/bin/omarchy-fix-qt-color
+if [[ ! -d /usr/share/omarchy/shell ]]; then
+  echo "  = no Omarchy shell; Qt Color fix not needed"
+elif "$fix" --check >/dev/null; then
+  echo "  = shell is clear of the Qt Color clash"
+elif [[ ${OMARCHY_SETUP_DRY:-0} == 1 ]]; then
+  echo "  ? would: $fix"
+elif "$fix" | sed 's/^/  /'; then
+  pgrep -x quickshell >/dev/null && command -v omarchy-restart-shell >/dev/null && omarchy-restart-shell
+else
+  echo "  ! Qt Color fix failed; run $fix by hand"
+fi