feat(db): remove unique constraint on Organization.wabaId

Allow multiple organizations to operate under the same WABA
(one WhatsApp Business Account, multiple phone numbers / orgs).
Migration applied directly on Neon — shadow DB blocked by pgvector.

packages/database/prisma/migrations/20260515000001_remove_waba_unique_constraint/migration.sql

@@ -0,0 +1,3 @@
+-- Allow multiple organizations to share the same WABA ID
+-- (e.g. multiple phone numbers under one Meta WhatsApp Business Account)
+DROP INDEX IF EXISTS "Organization_wabaId_key";

packages/database/prisma/schema.prisma

@@ -10,7 +10,7 @@ datasource db {
 model Organization {
   id                 String                @id @default(uuid())
   name               String
-  wabaId                   String?               @unique
+  wabaId                   String?
   metaBusinessId           String?
   systemUserToken          String?
   systemUserTokenIssuedAt  DateTime?