feat(auth): add TypeScript types for documented JWT claims fields

[SumitKumar-17]

• Added type safety for email, phone, user_metadata, app_metadata, is_anonymous, etc.
• Provides autocomplete and type safety for all documented JWT claims fields
• getClaims() method now returns properly typed JwtPayload with documented fields

Fixes #1584

🔍 Description

What changed?

Why was this change needed?

Closes #(issue_number)

📸 Screenshots/Examples

🔄 Breaking changes

• This PR contains no breaking changes

📋 Checklist

• I have read the Contributing Guidelines
• My PR title follows the conventional commit format: <type>(<scope>): <description>
• I have run npx nx format to ensure consistent code formatting
• I have added tests for new functionality (if applicable)
• I have updated documentation (if applicable)

📝 Additional notes

[mrbjjackson]

@SumitKumar-17 I'm not sure if this is the correct place to point this out but I'm just looking at your commit - I see you've added an "id" field. I'm not sure where this would come from. It's not mentioned in the docs as far as I can see - rather the claims object uses the "sub" parameter for the user's uuid.

[coveralls]

coverage: 95.455% (-0.5%) from 95.987%
when pulling 905f6a3 on SumitKumar-17:feat/typescript-jwt-claims
into 46abe0d on supabase:master.

[mandarini]

Hi @SumitKumar-17 ! Thank you for this PR. I discussed it why my team and we think this PR has a few incorrect claims added (e.g.: id, created_at, updated_at, phone_confirmed_at, etc...). We would recommend you use the following doc as the source of truth for the claims: https://supabase.com/docs/guides/auth/jwt-fields

One caveat here is that a user may use a custom access token hook so there's no guarantee the claims will exist (other than the required ones), so they should all be marked as optional.

Do you think you're able to make these changes? If not, let me know and we can help!