feat: 新增皮肤站原生登录与验证码弹窗

登录入口原先会切到主页并打开内嵌网页。改为弹出启动器自己的登录弹窗：

- SkinSiteLoginModal：账号密码校验规则与皮肤站一致，登录前走验证码，
  成功后保存 JWT 并刷新会话。
- SkinSiteCaptchaModal：拉取旋转图片验证码，用滑块调整角度后提交。
- AccountsCard 的登录按钮改为打开该弹窗，登录成功后重新拉取玩家列表。
- 修正 verifyCaptcha 的参数：服务端校验的是旋转角度 degree，不是文字答案。

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

@@ -244,6 +244,7 @@
 		</div>
 	</Accordion>
 	<MinecraftLoginModal ref="minecraftLoginModal" @complete="onMicrosoftLogin" />
+	<SkinSiteLoginModal ref="skinSiteLoginModal" @signed-in="onSkinSiteSignedIn" />
 </template>
 
 <script setup lang="ts">
@@ -269,12 +270,12 @@ import { useQueryClient } from '@tanstack/vue-query'
 import { listen } from '@tauri-apps/api/event'
 import type { Ref } from 'vue'
 import { computed, nextTick, onUnmounted, ref, watch } from 'vue'
-import { useRoute, useRouter } from 'vue-router'
+import { useRoute } from 'vue-router'
 
 import axolotlLogo from '@/assets/netherstar.png'
 import MinecraftLoginModal from '@/components/ui/MinecraftLoginModal.vue'
+import SkinSiteLoginModal from '@/components/ui/skin-site/SkinSiteLoginModal.vue'
 import {
-	openSkinSiteLogin,
 	requestSkinSitePlayers,
 	selectedSkinSitePlayerId,
 	selectSkinSitePlayer,
@@ -298,21 +299,20 @@ import { getPlayerHeadUrl } from '@/helpers/rendering/batch-skin-renderer.ts'
 import type { Skin } from '@/helpers/skins'
 import { get_available_skins } from '@/helpers/skins'
 import { handleSevereError } from '@/store/error.js'
-import { useTheming } from '@/store/state'
 
 const { formatMessage } = useVIntl()
 const { handleError } = injectNotificationManager()
 const { browserOffline, offline, refreshBrowserOffline } = useNetworkStatus()
 const queryClient = useQueryClient()
 const route = useRoute()
-const router = useRouter()
-const themeStore = useTheming()
+const skinSiteLoginModal = ref<InstanceType<typeof SkinSiteLoginModal>>()
 
 async function goToSkinSiteLogin() {
-	openSkinSiteLogin()
-	// The login action must reveal the iframe even if Minimal Home was selected.
-	themeStore.homeLayout = 'standard'
-	await router.push('/').catch(handleError)
+	skinSiteLoginModal.value?.show()
+}
+
+function onSkinSiteSignedIn() {
+	void requestSkinSitePlayers().catch(() => {})
 }
 const refreshingNetwork = ref(false)
 

apps/app-frontend/src/components/ui/skin-site/SkinSiteCaptchaModal.vue

@@ -0,0 +1,155 @@
+<script setup lang="ts">
+import {
+	commonMessages,
+	defineMessages,
+	injectNotificationManager,
+	NewModal,
+	useVIntl,
+} from '@modrinth/ui'
+import { computed, ref } from 'vue'
+
+import { requestCaptcha, verifyCaptcha } from '@/helpers/skin-site-api'
+
+const { formatMessage } = useVIntl()
+const { handleError } = injectNotificationManager()
+
+const messages = defineMessages({
+	title: { id: 'app.skin-site.captcha.title', defaultMessage: 'Let us check you are human' },
+	subtitle: {
+		id: 'app.skin-site.captcha.subtitle',
+		defaultMessage: 'Drag the slider to rotate the image upright.',
+	},
+	submit: { id: 'app.skin-site.captcha.submit', defaultMessage: 'Submit' },
+	loading: { id: 'app.skin-site.captcha.loading', defaultMessage: 'Loading captcha…' },
+})
+
+const emit = defineEmits<{ (e: 'verified', clientId: string): void; (e: 'cancel'): void }>()
+
+const modal = ref<InstanceType<typeof NewModal>>()
+const loading = ref(false)
+const submitting = ref(false)
+const image = ref('')
+const challengeClientId = ref('')
+const degree = ref(0)
+
+/** The image is rotated by the server; the slider counter-rotates the preview. */
+const previewRotation = computed(() => `${degree.value}deg`)
+
+function resetState() {
+	degree.value = 0
+	image.value = ''
+	challengeClientId.value = ''
+}
+
+async function loadCaptcha() {
+	loading.value = true
+	try {
+		const result = await requestCaptcha()
+		if (!result.success) throw new Error(result.errorMessage)
+		image.value = result.payload.image ?? ''
+		challengeClientId.value = result.payload.clientId
+		degree.value = 0
+	} catch (error) {
+		handleError(error)
+		modal.value?.hide()
+		emit('cancel')
+	} finally {
+		loading.value = false
+	}
+}
+
+async function show() {
+	resetState()
+	modal.value?.show()
+	await loadCaptcha()
+}
+
+async function submit() {
+	if (submitting.value || !challengeClientId.value) return
+	submitting.value = true
+	try {
+		const result = await verifyCaptcha({
+			clientId: challengeClientId.value,
+			degree: degree.value,
+		})
+		if (!result.success) {
+			handleError(new Error(result.errorMessage))
+			await loadCaptcha()
+			return
+		}
+		modal.value?.hide()
+		emit('verified', result.payload)
+	} catch (error) {
+		handleError(error)
+	} finally {
+		submitting.value = false
+	}
+}
+
+function cancel() {
+	modal.value?.hide()
+	emit('cancel')
+}
+
+defineExpose({ show })
+</script>
+
+<template>
+	<NewModal ref="modal" :header="formatMessage(messages.title)" @hide="resetState">
+		<div class="flex flex-col items-center gap-6">
+			<p class="m-0 text-secondary">{{ formatMessage(messages.subtitle) }}</p>
+
+			<div
+				class="size-44 overflow-hidden rounded-full border-4 border-solid border-bg-raised bg-button-bg"
+			>
+				<img
+					v-if="image"
+					:src="image"
+					alt=""
+					class="size-full object-cover transition-transform duration-75"
+					:style="{ transform: `rotate(${previewRotation})` }"
+					draggable="false"
+				/>
+			</div>
+
+			<div class="w-full max-w-sm">
+				<input
+					v-model.number="degree"
+					type="range"
+					min="0"
+					max="360"
+					step="1"
+					class="w-full accent-brand"
+					:disabled="loading || submitting"
+				/>
+				<div class="mt-1 flex justify-between text-xs text-secondary">
+					<span>0°</span>
+					<span>90°</span>
+					<span>180°</span>
+					<span>270°</span>
+					<span>360°</span>
+				</div>
+			</div>
+		</div>
+
+		<template #actions>
+			<div class="flex justify-end gap-2">
+				<button
+					type="button"
+					class="rounded-full px-4 py-2 text-secondary hover:bg-button-bg"
+					@click="cancel"
+				>
+					{{ formatMessage(commonMessages.cancelButton) }}
+				</button>
+				<button
+					type="button"
+					class="rounded-full bg-brand px-4 py-2 font-semibold text-contrast"
+					:disabled="loading || submitting || !image"
+					@click="submit"
+				>
+					{{ formatMessage(loading ? messages.loading : messages.submit) }}
+				</button>
+			</div>
+		</template>
+	</NewModal>
+</template>

apps/app-frontend/src/components/ui/skin-site/SkinSiteLoginModal.vue

@@ -0,0 +1,146 @@
+<script setup lang="ts">
+import {
+	commonMessages,
+	defineMessages,
+	injectNotificationManager,
+	NewModal,
+	StyledInput,
+	useVIntl,
+} from '@modrinth/ui'
+import { computed, ref } from 'vue'
+
+import { reloadSkinSiteSession, signInSkinSite } from '@/composables/skin-site-session'
+
+import SkinSiteCaptchaModal from './SkinSiteCaptchaModal.vue'
+
+const { formatMessage } = useVIntl()
+const { handleError, addNotification } = injectNotificationManager()
+
+const messages = defineMessages({
+	title: { id: 'app.skin-site.login.title', defaultMessage: 'Sign in to StarLight' },
+	username: { id: 'app.skin-site.login.username', defaultMessage: 'Username or email' },
+	password: { id: 'app.skin-site.login.password', defaultMessage: 'Password' },
+	signIn: { id: 'app.skin-site.login.sign-in', defaultMessage: 'Sign in' },
+	signingIn: { id: 'app.skin-site.login.signing-in', defaultMessage: 'Signing in…' },
+	usernameHint: {
+		id: 'app.skin-site.login.username-hint',
+		defaultMessage: '3–16 characters, or a registered email address.',
+	},
+	passwordHint: {
+		id: 'app.skin-site.login.password-hint',
+		defaultMessage: '6–50 characters with upper case, lower case and a digit.',
+	},
+	success: { id: 'app.skin-site.login.success', defaultMessage: 'Signed in to StarLight.' },
+})
+
+const PASSWORD_RE = /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{6,50}$/
+
+const modal = ref<InstanceType<typeof NewModal>>()
+const captchaModal = ref<InstanceType<typeof SkinSiteCaptchaModal>>()
+const username = ref('')
+const password = ref('')
+const working = ref(false)
+
+const emit = defineEmits<{ (e: 'signed-in' | 'cancel'): void }>()
+
+const usernameValid = computed(() => {
+	const value = username.value.trim()
+	if (!value) return false
+	if (value.includes('@')) return value.length < 64
+	return value.length >= 3 && value.length <= 16
+})
+
+const passwordValid = computed(() => PASSWORD_RE.test(password.value))
+const canSubmit = computed(() => usernameValid.value && passwordValid.value && !working.value)
+
+function reset() {
+	username.value = ''
+	password.value = ''
+	working.value = false
+}
+
+function show() {
+	reset()
+	modal.value?.show()
+}
+
+async function beginSignIn() {
+	if (!canSubmit.value) return
+	captchaModal.value?.show()
+}
+
+async function onCaptchaVerified(clientId: string) {
+	working.value = true
+	try {
+		const result = await signInSkinSite({
+			username: username.value.trim(),
+			password: password.value,
+			clientId,
+		})
+		if (!result.success) {
+			handleError(new Error(result.errorMessage))
+			return
+		}
+		await reloadSkinSiteSession()
+		addNotification({ type: 'success', title: formatMessage(messages.success) })
+		modal.value?.hide()
+		reset()
+		emit('signed-in')
+	} catch (error) {
+		handleError(error)
+	} finally {
+		working.value = false
+	}
+}
+
+function cancel() {
+	modal.value?.hide()
+	emit('cancel')
+}
+
+defineExpose({ show })
+</script>
+
+<template>
+	<NewModal ref="modal" :header="formatMessage(messages.title)" @hide="reset">
+		<div class="flex flex-col gap-4">
+			<label class="flex flex-col gap-1">
+				<span class="font-semibold text-contrast">{{ formatMessage(messages.username) }}</span>
+				<StyledInput v-model="username" type="text" autocomplete="username" />
+				<span class="text-xs text-secondary">{{ formatMessage(messages.usernameHint) }}</span>
+			</label>
+
+			<label class="flex flex-col gap-1">
+				<span class="font-semibold text-contrast">{{ formatMessage(messages.password) }}</span>
+				<StyledInput v-model="password" type="password" autocomplete="current-password" />
+				<span class="text-xs text-secondary">{{ formatMessage(messages.passwordHint) }}</span>
+			</label>
+		</div>
+
+		<template #actions>
+			<div class="flex justify-end gap-2">
+				<button
+					type="button"
+					class="rounded-full px-4 py-2 text-secondary hover:bg-button-bg"
+					@click="cancel"
+				>
+					{{ formatMessage(commonMessages.cancelButton) }}
+				</button>
+				<button
+					type="button"
+					class="rounded-full bg-brand px-4 py-2 font-semibold text-contrast disabled:opacity-50"
+					:disabled="!canSubmit"
+					@click="beginSignIn"
+				>
+					{{ formatMessage(working ? messages.signingIn : messages.signIn) }}
+				</button>
+			</div>
+		</template>
+	</NewModal>
+
+	<SkinSiteCaptchaModal
+		ref="captchaModal"
+		@verified="onCaptchaVerified"
+		@cancel="working = false"
+	/>
+</template>