feat(events): add tag validation to admin event create/edit routes

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

@@ -1,4 +1,5 @@
 import Event from '../../../models/event.js'
+import Tag from '../../../models/tag.js'
 import { connectDB } from '../../../utils/mongoose.js'
 import { requireAdmin } from '../../../utils/auth.js'
 
@@ -11,6 +12,19 @@ export default defineEventHandler(async (event) => {
 
     await connectDB()
 
+    // Validate tag slugs against Tag collection
+    if (body.tags && body.tags.length > 0) {
+      const foundTags = await Tag.find({ slug: { $in: body.tags } })
+      const foundSlugs = new Set(foundTags.map(t => t.slug))
+      const invalid = body.tags.filter(s => !foundSlugs.has(s))
+      if (invalid.length > 0) {
+        throw createError({
+          statusCode: 400,
+          statusMessage: `Unknown tag slugs: ${invalid.join(', ')}`
+        })
+      }
+    }
+
     const updateData = {
       ...body,
       startDate: new Date(body.startDate),