Fail the suite on privileged writes through unquoted heredocs

An installer that writes a root-owned file through a heredoc with an
unquoted delimiter (<<EOF rather than <<'EOF') has the installing user's
shell expand the body first, so a user-controlled value is baked in as a
literal. Send that into /etc and root later reads or executes a path the
unprivileged user picked: a udev rule carrying
$HOME/.local/share/omarchy/bin/... resolves through a symlink that user
owns, so replacing the symlink gets their code run as root.

Add the static check. A heredoc is flagged when its delimiter is
unquoted, its body contains an install-time expansion (escaped \$VAR does
not count, since that is left for a root daemon to expand at runtime),
and its output reaches /etc, /usr, /opt, /srv, /boot or /var/lib via sudo
tee, sudo dd, a redirect, or an install/cp/mv of the generated scratch
file. Destinations written as variables are resolved from the file's own
assignments.

Sites that genuinely need install-time expansion declare it inline:

  # omarchy:heredoc-expands paths=none -- $servers is a validated IP list

paths= is machine-checked against the expansions the scanner finds to be
path-shaped, so this cannot become a rubber stamp: adding a $HOME/... to
an already-annotated heredoc makes the declaration false and trips the
check again. Path expansions anchored under a root-owned prefix, as in
"/etc/systemd/system/$unit", are correctly not path-shaped.

Annotate the sites the scan reports, each of which expands a scalar: DNS
addresses in omarchy-dns, a literal PAM line in
omarchy-setup-security-fingerprint, kernel cmdline parameters and
usernames in omarchy-upgrade-to-quattro. omarchy-provision-owner expanded
a unit name that was already a constant, so its delimiter is now quoted
and the name hardcoded; the generated unit file is byte-identical.
omarchy-windows-vm declares paths=storage,shared, the only site that
interpolates a user-chosen path.

Fixtures prove non-vacuity in both directions: the write routes other
than a pipe into sudo tee, the shapes that must stay quiet, udev rules
and a shutdown unit taken verbatim from this repository's history, and
the rubber-stamp case where a paths=none annotation on a baked $HOME path
still fails.

bin/omarchy-dns

@@ -149,6 +149,9 @@ write_networkmanager_dns() {
   local servers="$1"
 
   install -d -m 0755 "$(dirname "$NM_DNS_CONF")"
+  # omarchy:heredoc-expands paths=none -- $servers is a space-separated list of
+  # validated DNS server addresses, not a path; nothing user-writable is baked
+  # into the root-owned drop-in.
   cat >"$NM_DNS_CONF" <<EOF
 # Managed by omarchy-dns. Remove this file or run omarchy dns DHCP to use DHCP DNS again.
 [global-dns]
@@ -302,6 +305,9 @@ Custom)
   split_dns_servers "$dns_servers"
   write_networkmanager_dns "$dns_servers"
   set_connection_dns "$ipv4_dns" "$ipv6_dns"
+  # omarchy:heredoc-expands paths=none -- $dns_servers holds DNS addresses that
+  # normalize_servers has already validated; the //,/ turns the comma list into
+  # the space list resolved.conf wants. No path is interpolated.
   tee /etc/systemd/resolved.conf >/dev/null <<EOF
 [Resolve]
 DNS=${dns_servers//,/ }