Add helper for displaying key ownership percentage for connected wallet

[Chucks1093]

Summary
When a user holds keys in a creator, the UI shows the raw key count but not what percentage of total supply that represents. A small helper that computes and displays the ownership percentage gives holders a clearer picture of their position.

Scope

• add a helper that computes ownership percentage from a holder balance and total supply
• display the percentage alongside the key count on the holdings view
• handle the zero-supply edge case gracefully

Acceptance Criteria

• the ownership percentage is displayed correctly next to the key count
• a zero total supply does not produce a divide-by-zero error
• the percentage updates when the supply or balance changes

Contributor coordination: if you pick this up, reach out in Telegram for updates or clarification: https://t.me/accesslayerorg

[LaahAbba]

@LaahAbba has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi I'm a full stack developer I'll like to work on this issue because It picks my interest and Ive got experience with similar projects I'll have it solved in 24 hours or less

ℹ️ Repo Maintainers: To accept this application, review their application or assign @LaahAbba to this issue.

[Praxhant97]

@Praxhant97 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Greetings, i would like to work on your accesslayer-client project! Displaying raw key counts without context hides the actual weight of a holder's position, and I have the specific frontend utility and state management development skills this project needs to integrate this clear ownership indicator. I am highly comfortable with TypeScript, React hook lifecycles, and writing defensive utility logic, which will allow me to seamlessly build a helper that computes the accurate percentage, safely handles the zero-supply edge case, and auto-updates alongside changing wallet or supply states on the holdings view.

Timeframe: 24 hours

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Praxhant97 to this issue.