Income taxes - Schedule of Reconciliation of Income Tax Benefit (Provision) with the Federal Statutory Tax Rate (Details)	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023
Reconciliation of provision for income taxes with federal statutory rate
U.S. statutory rate	21.00%	21.00%
State tax rate	0.90%	1.50%
Foreign rate differential	4.40%	0.50%
Permanent differences	(6.70%)	(0.10%)
Impact of sale of ARCA Recycling and Canada	0.00%	(4.40%)
Change in valuation allowance	12.90%	(25.70%)
Other	0.20%	(0.10%)
Effective income tax rate	32.70%	(7.30%)