feat: 重做新手导览

按新的顺序重写 main 导览（10 个内容点，导航 + 高亮共 16 步）：
主页、登录 StarLight、侧栏公告、创建 StarLight 实例、发现内容、
皮肤选择器、实例库、实验室、下载、设置的更新页。

- onboardingConfig.ts 重写 onboardingTours.main，并新增 home-intro/
  account-login/announcement/create-starlight/settings-updates 文案；
- HomeAnnouncementEntry.vue 增加 data-onboarding-id="home-announcement"
  锚点；
- en-US / zh-CN 补齐上述新增文案。

apps/app-frontend/src/locales/en-US/index.json

@@ -5975,6 +5975,36 @@
   "app.onboarding.welcome.title": {
     "message": "Everything is ready"
   },
+  "app.onboarding.home-intro.title": {
+    "message": "Welcome home"
+  },
+  "app.onboarding.home-intro.description": {
+    "message": "This is your home page. It shows your instances, recent activity, and quick shortcuts to get playing."
+  },
+  "app.onboarding.account-login.title": {
+    "message": "Sign in to StarLight"
+  },
+  "app.onboarding.account-login.description": {
+    "message": "Sign in to the StarLight skin site here to use your StarLight players, install hosted modpacks, and sync your account."
+  },
+  "app.onboarding.announcement.title": {
+    "message": "Latest announcements"
+  },
+  "app.onboarding.announcement.description": {
+    "message": "Open the announcement entry in the sidebar to read the latest news, rules, and server notices."
+  },
+  "app.onboarding.create-starlight.title": {
+    "message": "Create a StarLight instance"
+  },
+  "app.onboarding.create-starlight.description": {
+    "message": "Use Create new instance here. A StarLight instance installs the server-selected modpack and versions, then keeps them updated before each launch."
+  },
+  "app.onboarding.settings-updates.title": {
+    "message": "Stay up to date"
+  },
+  "app.onboarding.settings-updates.description": {
+    "message": "The Updates tab controls the update channel, checks for new launcher versions, and shows the changelog."
+  },
   "app.project.curseforge.loading": {
     "message": "Loading CurseForge project…"
   },