feat: User services

prisma/models/organization-join-request.prisma

@@ -0,0 +1,16 @@
+model OrganizationJoinRequest {
+  userId       String
+  orgId        String
+  status       ORGANIZATION_JOIN_REQUEST @default(PENDING)
+  requestedOn  DateTime                  @default(now())
+  rejectReason String?
+
+  @@unique([userId, orgId])
+  @@map("organization_join_request")
+}
+
+enum ORGANIZATION_JOIN_REQUEST {
+  PENDING
+  ACCEPTED
+  REJECTED
+}