This PR closes the first step of https://github.com/twentyhq/core-team-issues/issues/1451, about z-index fine-tuning on the table. The core part was to succeed in having the hovered portal and the surrounding cells switch their z-index to have the borders overlap nicely in all scrolling cases. See associated video for the new behavior. This PR fixes two majors UX issues we had : - The sticky column and row were sliding a bit on the beginning of the scroll - Too many components were re-rendering while we only needed to isolate those who presented a complex use case In the end, we isolated some very specific components like the cell 0-0 and the first scrollable header cell, which were giving the most problems with the hovered portal. This allows to leave the rest of the cells and header cells alone with those concerns because they weren't involved at all in z-index update, once we isolated those components. ## Demo https://github.com/user-attachments/assets/cbe630ed-63c3-4e86-a22e-a11662c6082c https://github.com/user-attachments/assets/36e6947d-9f89-4ed2-ba6c-cbb13016d7d1