user profile's backgrounds support

src/stores/interface.js

@@ -60,6 +60,7 @@ export const useInterfaceStore = defineStore('interface', {
     globalNotices: [],
     layoutHeight: 0,
     lastTimeline: null,
+    foreignProfileBackground: null,
   }),
   actions: {
     setTemporaryChanges({ confirm, revert }) {
@@ -96,6 +97,9 @@ export const useInterfaceStore = defineStore('interface', {
         console.error(`${error}`)
       }
     },
+    setForeignProfileBackground(url) {
+      this.foreignProfileBackground = url
+    },
     settingsSaved({ success, error }) {
       if (success) {
         if (this.noticeClearTimeout) {