fix: validate basename avatar aspect ratio and clear stale todo

[Dark-Brain07]

What changed? Why?

• Updated validateBasenameAvatarFile to be asynchronous: Implemented aspect ratio validation using createImageBitmap to ensure uploaded avatars are roughly square (ratio 0.8 - 1.25), fulfilling a TODO in usernames.ts.
• Updated UsernameAvatarField: Refactored the component to handle the asynchronous nature of the validation function, ensuring proper state management during validation.
• Cleaned up Footer: Removed a stale // TODO: add discord link comment in Footer.tsx as the link was already present.

Notes to reviewers

• The validateBasenameAvatarFile function was converted to async to allow for image bitmap creation, which is necessary for checking dimensions.
• useEffect in UsernameAvatarField now includes a mounted check to prevent state updates on unmounted components during the async validation.

How has it been tested?

• Manual verification of logic correctness for async validation handling.
• Confirmed Footer link presence visually in code.

Have you tested the following pages?

BaseWeb

• base.org (Footer change)
• base.org/names
• base.org/builders
• base.org/ecosystem
• base.org/name/jesse
• base.org/manage-names
• base.org/resources

[vercel]

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[cb-heimdall]

🟡 Heimdall Review Status

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