Summary: Added YCF Start 88SE pitbike

Why It Matters: This shows a new product is now for sale.

What Changed:

• Removed a link to "motoekipirovka" from the main navigation.
• Added a new product, "Питбайк YCF Start 88SE (2025)", to the "Новинки" (New Arrivals) section.
• Removed a news article about "Соревнования по Эндуро на Мотоциклах: « Левый Берег » – Piviha Hard Enduro".