Keep Settings recovery isolated and display-safe

tests/quickshell/settings-backup-contract.sh

@@ -79,16 +79,20 @@ absent_result="$(run restore "$absent_name")" || fail 'restore failed for a snap
 jq -e '.home.present == false and (.home | has("data") | not)' <<<"$absent_result" >/dev/null \
     || fail 'restore did not return absent Home state for the live service to reload'
 
-# Desktop absence is symmetric: a Home-only snapshot removes a desktop file
-# created later and restores the Home store.
+# Desktop absence is symmetric for ordinary preferences, but confirmed display
+# geometry is protected state: it must survive even a Home-only snapshot.
 rm -f "$settings"
 printf '{"initialized":true,"favorites":[{"id":"light.porch","alias":"Porch"}]}' >"$home"
 run save >/dev/null || fail 'save failed when desktop settings were absent'
 desktop_absent_name="$(run list | jq -r '.[0].name')"
-printf '{"gapsOut":47}' >"$settings"
+printf '{"gapsOut":47,"windowRounding":9,"displays":{"DP-2":{"mode":"4500x3000@60","scale":1.5,"transform":0}}}' >"$settings"
 printf '{"initialized":false,"favorites":[]}' >"$home"
 run restore "$desktop_absent_name" >/dev/null || fail 'Home-only snapshot restore failed'
-[[ ! -e "$settings" ]] || fail 'restore did not preserve the snapshot’s absent desktop state'
+[[ -e "$settings" ]] || fail 'Home-only restore discarded confirmed display geometry'
+[[ "$(jq -r '.displays["DP-2"].scale' "$settings")" == "1.5" ]] \
+    || fail 'Home-only restore changed confirmed display geometry'
+[[ "$(jq 'keys == ["displays"]' "$settings")" == "true" ]] \
+    || fail 'Home-only restore retained ordinary desktop preferences'
 [[ "$(jq -r '.favorites[0].id' "$home")" == "light.porch" ]] \
     || fail 'Home-only snapshot did not restore Home state'
 assert_transaction_clean