refactor: 移除内嵌皮肤站页面

主页已改为原生界面，整页内嵌网页不再需要：

- 删除 SkinSiteFrame.vue 与 StarlightSkin.vue。
- 移除 /starlight-skin 路由。
- 删除不再使用的 skinSiteFrameUrl 导出。
- 实例玩家弹窗的"去皮肤站登录"改为直接打开登录弹窗，不再跳转页面。

apps/app-frontend/src/components/instance/InstancePlayerModal.vue

@@ -1,11 +1,10 @@
 <script setup lang="ts">
 import { ButtonStyled, NewModal, useVIntl } from '@modrinth/ui'
 import { computed, onUnmounted, ref, watch } from 'vue'
-import { useRouter } from 'vue-router'
 
 import MinecraftLoginModal from '@/components/ui/MinecraftLoginModal.vue'
+import SkinSiteLoginModal from '@/components/ui/skin-site/SkinSiteLoginModal.vue'
 import {
-	openSkinSiteLogin,
 	requestSkinSitePlayers,
 	skinSitePlayers,
 	skinSiteStatus,
@@ -28,7 +27,7 @@ const { formatMessage } = useVIntl()
 
 const modal = ref<InstanceType<typeof NewModal>>()
 const microsoftLogin = ref<InstanceType<typeof MinecraftLoginModal>>()
-const router = useRouter()
+const skinSiteLoginModal = ref<InstanceType<typeof SkinSiteLoginModal>>()
 const accounts = ref<PlayerChoice[]>([])
 const active = ref(false)
 const loading = ref(false)
@@ -137,9 +136,8 @@ function signInSkinSite() {
 	rejectSelection?.(new PlayerSelectionNavigatedAwayError())
 	resolveSelection = undefined
 	rejectSelection = undefined
-	openSkinSiteLogin()
+	skinSiteLoginModal.value?.show()
 	modal.value?.hide()
-	void router.push('/starlight-skin')
 }
 
 const unregister = registerInstancePlayerPicker((id, saved) => {
@@ -246,5 +244,6 @@ onUnmounted(() => {
 			<p v-if="saving" class="m-0" role="status">{{ formatMessage(messages.saving) }}</p>
 		</div>
 	</NewModal>
+	<SkinSiteLoginModal ref="skinSiteLoginModal" @signed-in="refresh" />
 	<MinecraftLoginModal ref="microsoftLogin" @complete="refresh" />
 </template>

apps/app-frontend/src/components/ui/SkinSiteFrame.vue

@@ -1,23 +0,0 @@
-<script setup lang="ts">
-import { defineMessages, useVIntl } from '@modrinth/ui'
-
-import { skinSiteFrameUrl } from '@/composables/skin-site-session'
-
-const { formatMessage } = useVIntl()
-const messages = defineMessages({
-	frameTitle: {
-		id: 'app.starlight-skin.frame-title',
-		defaultMessage: 'StarLight Skin Site',
-	},
-})
-
-</script>
-
-<template>
-	<iframe
-		:src="skinSiteFrameUrl"
-		allow="clipboard-write; clipboard-read"
-		:title="formatMessage(messages.frameTitle)"
-		class="block h-full min-h-0 w-full border-0"
-	/>
-</template>

apps/app-frontend/src/composables/skin-site-session.ts

@@ -274,12 +274,6 @@ export async function requestSkinSiteLuck(): Promise<number> {
 // Legacy compatibility
 // ---------------------------------------------------------------------------
 
-/**
- * @deprecated The home view renders the skin site natively now. Kept only so
- * the transitional `SkinSiteFrame.vue` still compiles until it is replaced.
- */
-export const skinSiteFrameUrl = readonly(ref(`${SKIN_SITE_ORIGIN}/`))
-
 /**
  * Replace a player's skin texture.
  *

apps/app-frontend/src/pages/StarlightSkin.vue

@@ -1,9 +0,0 @@
-<script setup lang="ts">
-import SkinSiteFrame from '@/components/ui/SkinSiteFrame.vue'
-</script>
-
-<template>
-	<div class="h-full min-h-0">
-		<SkinSiteFrame />
-	</div>
-</template>

apps/app-frontend/src/routes.js

@@ -93,14 +93,6 @@ export default new createRouter({
 				discordActivity: 'Changing skins...',
 			},
 		},
-		{
-			path: '/starlight-skin',
-			name: 'Starlight skin',
-			component: () => import('@/pages/StarlightSkin.vue'),
-			meta: {
-				breadcrumb: [{ name: 'Starlight skin' }],
-			},
-		},
 		{
 			path: '/screenshots',
 			name: 'Screenshots',