perf(medusa): O(n) translations batch matching via Set lookups

The translations batch endpoint matched fetched rows against the workflow
result with translations.filter(t => result.created.some(r => r.id === t.id)),
once per row — O(n²) over the batch size, which is user-controlled. Build Sets
of created/updated ids once and test membership in O(1). Mirrors the existing
Set-based id dedup a few lines above. Behaviour is identical.

Author: yoo-minho

.changeset/translations-batch-set-lookup.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/medusa": patch
+---
+
+perf(medusa): avoid O(n²) matching in the translations batch endpoint by using Sets for created/updated id lookups

packages/medusa/src/api/admin/translations/batch/route.ts

@@ -47,12 +47,11 @@ export const POST = async (
     },
   })
 
-  const created = translations.filter((t) =>
-    result.created.some((r) => r.id === t.id)
-  )
-  const updated = translations.filter((t) =>
-    result.updated.some((r) => r.id === t.id)
-  )
+  const createdIds = new Set(result.created.map((r) => r.id))
+  const updatedIds = new Set(result.updated.map((r) => r.id))
+
+  const created = translations.filter((t) => createdIds.has(t.id))
+  const updated = translations.filter((t) => updatedIds.has(t.id))
 
   return res.status(200).json({
     created,