fix: backend TS errors — agent role type, WebSocket SocketStream, jwt.sign cast

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/routes/workstations.ts

@@ -173,7 +173,8 @@ const workstationRoutes: FastifyPluginAsync = async (fastify) => {
       )
 
       // Выдаём токен агенту (подписываем как обычный JWT с role=agent)
-      const token = fastify.jwt.sign(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const token = (fastify.jwt.sign as any)(
         {
           sub:          agent_id,
           role:         'agent',