fix: preserve query case in brand lookup cache key (#133)

Drop the .toLowerCase() call when building the cache key's targetValue so
it matches whatever detectTarget returns. detectTarget already normalizes
domains to lowercase; keywords are passed through as-is, so lowercasing
again folded otherwise-distinct keyword queries into the same cache
entry.

src/server/features/ai-search/services/brandLookup.ts

@@ -48,7 +48,7 @@ export async function getBrandLookup(
     organizationId: billingCustomer.organizationId,
     projectId: input.projectId,
     targetType: detected.type,
-    targetValue: detected.value.toLowerCase(),
+    targetValue: detected.value,
     locationCode: input.locationCode,
     languageCode: input.languageCode,
   });