[Bug] Correction of the Kanban page layout (horizontal and vertical scrolling)

[NdekoCode]

Fixing the Header on the Kanban Page and Correcting the Scrolling

The layout of the Kanban page must allow horizontal scrolling for the columns and vertical scrolling for the cards, without the header scrolling.

https://github.com/user-attachments/assets/64a86e0d-2e13-4e08-86df-cf7ee5ea3420

Steps to reproduce

1. Go to the Kanban page.
2. Try scrolling horizontally and vertically.
3. Observe whether the main header is visible and remains fixed and whether the kanban header scrolls or remains fixed.

Solution expected

• Fix the header of the Kanban page so that it does not scroll, when scrolling App header should be fixed (not scrolling)
• Allow horizontal scrolling for columns and vertical scrolling for cards only.

Acceptance Criteria

• The header must remain fixed when scrolling.
• The page must scroll vertically for cards and horizontally for columns.