Add a top-N limit control to the leaderboard view

[Muskankr]

Let users choose how many skills to show (e.g. top 10 / 25 / 50) rather than a fixed, potentially overwhelming list.

Acceptance criteria:

Simple control (dropdown or tab) for top-N selection
Defaults to a reasonable number (e.g. top 10)
Persists selection while switching tracks/sort mode

[Pranitrane]

I want work on this issue, please assign it to me.
I have previously resolve issue of cookie consent banner in this project.
Requesting you to assign it to me.