Merge quattro into the Chromium first-run EULA branch

Quattro stopped making the Chromium managed-policy directory world-writable while this branch was open, and the block it deleted from the theme install leaf sat directly above the comment this branch rewrites, so the two edits landed in one hunk. The resolution keeps the hardening — the policy directory is set up through install/config/browser-policy.sh now — along with the first-run seed and the comment that names both things the seed does.

bin/omarchy-upgrade-to-quattro

@@ -1312,7 +1312,21 @@ apply_system_transition() {
     /usr/share/icons/Yaru/scalable/actions/go-next-symbolic.svg
   as_root gtk-update-icon-cache /usr/share/icons/Yaru >/dev/null 2>&1 || true
 
-  as_root install -d -m 0777 /etc/chromium/policies/managed
+  local browser_policy_helper=/usr/share/omarchy/install/helpers/browser-policy.sh
+  if ! as_root test -f "$browser_policy_helper"; then
+    warn "$browser_policy_helper is unavailable; Chromium policy directories were not hardened."
+  else
+    as_root env OMARCHY_PATH=/usr/share/omarchy \
+      bash -euo pipefail -c '
+        source "$OMARCHY_PATH/install/helpers/browser-policy.sh"
+        browser_policy_setup_dir /etc/chromium/policies/managed
+        for dir in "${BROWSER_POLICY_MANAGED_DIRS[@]}"; do
+          [[ $dir == "/etc/chromium/policies/managed" ]] && continue
+          [[ -d $dir || -L $dir ]] || continue
+          browser_policy_setup_dir "$dir"
+        done
+      '
+  fi
   as_root install -d -m 0755 /usr/lib/chromium
   printf '%s\n' '{"distribution":{"require_eula":false},"browser":{"theme":{"color_scheme":0,"color_scheme2":0}}}' | \
     as_root tee /usr/lib/chromium/initial_preferences >/dev/null
@@ -2306,6 +2320,11 @@ refresh_current_theme_after_upgrade() {
   # hooks because one of them runs `hyprctl reload`. Still poke terminal
   # emulators so the active upgrade terminal picks up generated theme files.
   run_as_user_omarchy omarchy-restart-terminal >/dev/null 2>&1 || true
+
+  # apply_system_transition purged user-owned color.json. Headless theme-set
+  # skipped omarchy-theme-set-browser, so rewrite the colour here.
+  run_as_user_omarchy omarchy-theme-set-browser >/dev/null 2>&1 ||
+    warn "Could not apply browser theme colour. Run 'omarchy theme set \"$theme_name\"' after reboot if Chromium's theme looks stale."
 }
 
 # Everything below mutates the system, so a non-zero exit from here on leaves a