feat: migrate Canvas and Groups API to Prisma ORM

app/server/api/groups/[id].delete.ts

@@ -1,20 +1,17 @@
 import { requireAuth } from '~/server/utils/auth'
-import { groups, userGroups } from '~/server/utils/db'
+import { prisma } from '~/server/utils/prisma'
 
 export default defineEventHandler(async (event) => {
   const user = requireAuth(event)
   const groupId = getRouterParam(event, 'id')!
 
-  const group = groups.get(groupId)
+  const group = await prisma.group.findUnique({ where: { id: groupId } })
   if (!group) throw createError({ statusCode: 404, message: 'Group not found' })
   if (group.ownerId !== user.id && user.role !== 'admin') {
     throw createError({ statusCode: 403, message: 'Only owner can delete group' })
   }
 
-  groups.delete(groupId)
-  for (const [key] of userGroups) {
-    if (key.endsWith(`-${groupId}`)) userGroups.delete(key)
-  }
+  await prisma.group.delete({ where: { id: groupId } })
 
   return { success: true }
 })