Merge branch 'misskey-develop' into merge/2025-03-24

# Conflicts:
#	.github/workflows/api-misskey-js.yml
#	.github/workflows/changelog-check.yml
#	.github/workflows/check-misskey-js-autogen.yml
#	.github/workflows/get-api-diff.yml
#	.github/workflows/lint.yml
#	.github/workflows/locale.yml
#	.github/workflows/on-release-created.yml
#	.github/workflows/storybook.yml
#	.github/workflows/test-backend.yml
#	.github/workflows/test-federation.yml
#	.github/workflows/test-frontend.yml
#	.github/workflows/test-misskey-js.yml
#	.github/workflows/test-production.yml
#	.github/workflows/validate-api-json.yml
#	locales/index.d.ts
#	package.json
#	packages/misskey-js/generator/package.json
#	packages/misskey-js/package.json
#	pnpm-lock.yaml
#	scripts/changelog-checker/package-lock.json
#	scripts/changelog-checker/package.json

packages/frontend/src/preferences/def.ts

@@ -431,6 +431,9 @@ export const PREF_DEF = {
 	'deck.navbarPosition': {
 		default: 'left' as 'left' | 'top' | 'bottom',
 	},
+	'deck.wallpaper': {
+		default: null as string | null,
+	},
 
 	'chat.showSenderName': {
 		default: false,