feat: 后台管理系统完整重构 + 前后台数据联通

- 后台全面引入 Naive UI 组件库，统一 UI 规范
- 前台 usePublicApi 切换到 API 调用（GET /api/content/[key]）
- 前后台数据源统一（site_content 表）
- 产品线统一管理（tour/camp/course 三套编辑器）
- 产品数据归一化（itinerary/faq/pricing 格式统一）
- 表单提交 API 改写入 submissions 表
- 新增 submissions 标记已读 API
- site-content PUT 支持 upsert
- 修复前台 bug（stories 路由冲突、占位符警告、selector breadcrumb）
- 消除 PageHero 类型警告（useSEO reactive 修复）
- 25 个前台页面全部 HTTP 200，展示效果不变

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/api/admin/stories/[id].delete.js

@@ -0,0 +1,11 @@
+import { eq } from 'drizzle-orm'
+import { useDB, schema } from '../../../utils/db.js'
+import { requireAdmin } from '../../../utils/auth.js'
+
+export default defineEventHandler(async (event) => {
+  requireAdmin(event)
+  const id = Number(getRouterParam(event, 'id'))
+  const db = useDB()
+  db.delete(schema.stories).where(eq(schema.stories.id, id)).run()
+  return { success: true }
+})

server/api/admin/stories/[id].get.js

@@ -0,0 +1,12 @@
+import { eq } from 'drizzle-orm'
+import { useDB, schema } from '../../../utils/db.js'
+import { requireAdmin } from '../../../utils/auth.js'
+
+export default defineEventHandler(async (event) => {
+  requireAdmin(event)
+  const id = Number(getRouterParam(event, 'id'))
+  const db = useDB()
+  const item = db.select().from(schema.stories).where(eq(schema.stories.id, id)).get()
+  if (!item) throw createError({ statusCode: 404, message: '故事不存在' })
+  return item
+})

server/api/admin/stories/[id].put.js

@@ -0,0 +1,32 @@
+import { eq } from 'drizzle-orm'
+import { useDB, schema } from '../../../utils/db.js'
+import { requireAdmin } from '../../../utils/auth.js'
+
+export default defineEventHandler(async (event) => {
+  requireAdmin(event)
+
+  const id = Number(getRouterParam(event, 'id'))
+  const body = await readBody(event)
+  const db = useDB()
+
+  const updateData = {}
+  if (body.title !== undefined) updateData.title = body.title
+  if (body.slug !== undefined) updateData.slug = body.slug
+  if (body.subtitle !== undefined) updateData.subtitle = body.subtitle
+  if (body.familyType !== undefined) updateData.familyType = body.familyType
+  if (body.childrenAge !== undefined) updateData.childrenAge = body.childrenAge
+  if (body.fromCity !== undefined) updateData.fromCity = body.fromCity
+  if (body.tripProduct !== undefined) updateData.tripProduct = body.tripProduct
+  if (body.travelDate !== undefined) updateData.travelDate = body.travelDate
+  if (body.coverImage !== undefined) updateData.coverImage = body.coverImage
+  if (body.sections !== undefined) updateData.sections = JSON.stringify(body.sections)
+  if (body.keyMoments !== undefined) updateData.keyMoments = JSON.stringify(body.keyMoments)
+  if (body.seoTitle !== undefined) updateData.seoTitle = body.seoTitle
+  if (body.seoDesc !== undefined) updateData.seoDesc = body.seoDesc
+  if (body.published !== undefined) updateData.published = body.published ? 1 : 0
+  if (body.sortOrder !== undefined) updateData.sortOrder = body.sortOrder
+
+  db.update(schema.stories).set(updateData).where(eq(schema.stories.id, id)).run()
+
+  return { success: true }
+})