fix: branch selector dropdown clipping and scroll reset on tab switch

[AbhiVarde]

Problem

Two issues with the branch selector dropdown:

• Dropdown was being clipped by a parent scroll container when there were few files in the repo, making it appear cut off
• Switching between Branches and Tags tabs preserved the previous scroll position instead of resetting to the top

Solution

• Changed dropdown from absolute to fixed positioning using triggerRef to calculate the correct viewport position, so it always renders above parent scroll containers
• Added listRef to the scrollable list and reset scroll to 0 on each tab switch via scrollTo(0, 0)

Files Changed

• apps/web/src/components/repo/branch-selector.tsx

Screenshots

Before	After

[vercel]

@AbhiVarde is attempting to deploy a commit to the better-auth Team on Vercel.

A member of the Team first needs to authorize it.