ADD - separate Home and Lock wallpapers

Store independent Home Screen and Lock Screen wallpaper selections, preserve legacy preferences, and route gallery or camera picks to the selected destination. Add the Settings segmented selector and contract coverage.

frontend/src/stores/phone.ts

@@ -19,6 +19,7 @@ import {
   type AppNotificationPreferences,
   type PhonePreferencesV1,
   type WallpaperId,
+  type WallpaperTarget,
 } from '@/utils/preferences'
 
 type LocaleTree = Record<string, unknown>
@@ -4062,6 +4063,9 @@ const defaultLocales: LocaleTree = {
       wallpaperFromCameraDescription: 'Create a new wallpaper',
       wallpaperHistory: 'Recent',
       wallpaperCustom: 'Photo wallpaper',
+      wallpaperTarget: 'Wallpaper destination',
+      wallpaperHomeScreen: 'Home Screen',
+      wallpaperLockScreen: 'Lock Screen',
       toggle: {
         airplaneMode: 'Toggle Airplane Mode',
         streamerMode: 'Toggle Streamer Mode',
@@ -4654,15 +4658,26 @@ export const usePhoneStore = defineStore('phone', {
     setSystemDarkMode(value: boolean): void {
       this.systemDarkMode = value
     },
-    setWallpaper(wallpaper: WallpaperId, imageUrl: string | null = null): void {
+    setWallpaper(
+      wallpaper: WallpaperId,
+      imageUrl: string | null = null,
+      target: WallpaperTarget | 'both' = 'home',
+    ): void {
       const normalizedImageUrl =
         wallpaper === 'custom' ? imageUrl?.trim() : null
       if (wallpaper === 'custom' && !normalizedImageUrl) {
         throw new Error('Custom wallpapers require a photo URL.')
       }
 
-      this.preferences.settings.wallpaper = wallpaper
-      this.preferences.settings.wallpaperImageUrl = normalizedImageUrl ?? null
+      if (target === 'home' || target === 'both') {
+        this.preferences.settings.wallpaper = wallpaper
+        this.preferences.settings.wallpaperImageUrl = normalizedImageUrl ?? null
+      }
+      if (target === 'lock' || target === 'both') {
+        this.preferences.settings.lockWallpaper = wallpaper
+        this.preferences.settings.lockWallpaperImageUrl =
+          normalizedImageUrl ?? null
+      }
       this.preferences.settings.wallpaperHistory = [
         { imageUrl: normalizedImageUrl ?? null, wallpaper },
         ...this.preferences.settings.wallpaperHistory.filter((entry) =>