fix: import block syntax in split dashboard files

- Add missing closing ) in clients.go, providers_admin.go, users.go, system.go
- Add SetTimeout(30s) to OpenAI provider (was resty.New() with no timeout)

internal/server/users.go

@@ -17,6 +17,7 @@ import (
 	"log/slog"
 
 	"github.com/shirou/gopsutil/v3/cpu"
+)
 
 func (s *Server) handleGetUsers(c *gin.Context) {
 	var users []db.User