fix: move AddOrganizationMembers RPC to AdminService

This is a superadmin-only operation. Move from FrontierService to
AdminService where authorization checks IsSuperUser.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: whoAbhishekSah

raystack/frontier/v1beta1/admin.proto

@@ -27,6 +27,8 @@ service AdminService {
 
   rpc AdminCreateOrganization(AdminCreateOrganizationRequest) returns (AdminCreateOrganizationResponse) {}
 
+  rpc AddOrganizationMembers(AddOrganizationMembersRequest) returns (AddOrganizationMembersResponse) {}
+
   rpc SearchOrganizations(SearchOrganizationsRequest) returns (SearchOrganizationsResponse) {}
 
   rpc SearchOrganizationUsers(SearchOrganizationUsersRequest) returns (SearchOrganizationUsersResponse) {}
@@ -1078,3 +1080,23 @@ message SearchOrganizationPATsResponse {
   repeated OrganizationPAT organization_pats = 1;
   RQLQueryPaginationResponse pagination = 2;
 }
+
+message AddOrganizationMembersRequest {
+  string org_id = 1 [(buf.validate.field).string.uuid = true];
+  repeated OrgMemberEntry members = 2;
+}
+
+message OrgMemberEntry {
+  string user_id = 1 [(buf.validate.field).string.uuid = true];
+  string role_id = 2 [(buf.validate.field).string.uuid = true];
+}
+
+message AddOrganizationMembersResponse {
+  repeated OrgMemberResult results = 1;
+}
+
+message OrgMemberResult {
+  string user_id = 1;
+  bool success = 2;
+  string error = 3;
+}

raystack/frontier/v1beta1/frontier.proto

@@ -133,8 +133,6 @@ service FrontierService {
 
   rpc SetOrganizationMemberRole(SetOrganizationMemberRoleRequest) returns (SetOrganizationMemberRoleResponse) {}
 
-  rpc AddOrganizationMembers(AddOrganizationMembersRequest) returns (AddOrganizationMembersResponse) {}
-
   rpc GetOrganizationKyc(GetOrganizationKycRequest) returns (GetOrganizationKycResponse) {}
 
   // Deprecated: use ListServiceUsers instead
@@ -1599,26 +1597,6 @@ message SetOrganizationMemberRoleRequest {
 
 message SetOrganizationMemberRoleResponse {}
 
-message AddOrganizationMembersRequest {
-  string org_id = 1 [(buf.validate.field).string.uuid = true];
-  repeated OrgMemberEntry members = 2;
-}
-
-message OrgMemberEntry {
-  string user_id = 1 [(buf.validate.field).string.uuid = true];
-  string role_id = 2 [(buf.validate.field).string.uuid = true];
-}
-
-message AddOrganizationMembersResponse {
-  repeated OrgMemberResult results = 1;
-}
-
-message OrgMemberResult {
-  string user_id = 1;
-  bool success = 2;
-  string error = 3;
-}
-
 message ListOrganizationServiceUsersRequest {
   string id = 1 [(buf.validate.field).string.min_len = 3];
 }