Fix: Add product name to recycled content slider keys

Prevents duplicate element ID error when switching products
by making slider keys unique per product.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.py

@@ -286,7 +286,7 @@ if has_materials and has_labor and has_overhead:
                         max_value=100,
                         value=int(default_pct * 100),
                         step=5,
-                        key=f"recycled_{component_key}",
+                        key=f"recycled_{selected_product}_{component_key}",
                         help=f"Virgin: €{component['virgin_cost_per_kg']:.2f}/kg, Recycled: €{component.get('recycled_cost_per_kg', component['virgin_cost_per_kg']):.2f}/kg"
                     )
                 col_idx += 1