Retail gross margin bridge: markdowns, mix, shrink, freight

Create a retail gross margin bridge for {period}.

Inputs:
- Sales and COGS by category: {sales_cogs}
- Markdown and promo data: {markdown_promo}
- Shrink data: {shrink}
- Freight and duties: {freight_duties}
- Mix metrics (units, ASP): {mix_metrics}

Output:
1) GM% bridge: prior → drivers → current (quantified).
2) Category-level insights (top movers).
3) Action recommendations (pricing, promos, shrink control, logistics).
4) Data checks and reconciliation notes.

Present as clear tables and short commentary.