feat: added heartbeat and fixed up gateway page

backend/src/db/migrations/20250825131627_add-gateway-v2-pki-and-ssh-configs.ts

@@ -120,6 +120,8 @@ export async function up(knex: Knex): Promise<void> {
       t.foreign("proxyId").references("id").inTable(TableName.Proxy).onDelete("SET NULL");
 
       t.string("name").notNullable().unique();
+
+      t.dateTime("heartbeat");
     });
 
     await createOnUpdateTrigger(knex, TableName.GatewayV2);

backend/src/db/schemas/gateways-v2.ts

@@ -14,7 +14,8 @@ export const GatewaysV2Schema = z.object({
   orgId: z.string().uuid(),
   identityId: z.string().uuid(),
   proxyId: z.string().uuid().nullable().optional(),
-  name: z.string()
+  name: z.string(),
+  heartbeat: z.date().nullable().optional()
 });
 
 export type TGatewaysV2 = z.infer<typeof GatewaysV2Schema>;