Add Support for Limiting M2M Usage via Tenant-Wide Defaults and Client/Organization Overrides

[developerkunal]

🔧 Changes

This PR introduces support for configuring token quotas for M2M (client credentials) flows at the tenant, client, and organization levels.

Key Changes:

• Introduced a unified TokenQuota struct used across tenant, client, and organization resources
• TenantDefaultTokenQuota now allows configuring default quotas for both clients and organizations
• Clients and organizations can override the tenant-wide quota by setting their own token_quota field
• Introduced TokenQuotaClientCredentials, which supports:
  • enforce: whether the quota is strictly enforced or just logged
  • per_day and per_hour limits for issued tokens

Unsetting Quotas

To remove a previously set quota, send a PATCH request with a null value:

# Unset tenant-wide quotas
PATCH /api/v2/tenants/settings
{
  "default_token_quota": null
}

# Unset client-specific quota
PATCH /api/v2/clients/{id}
{
  "token_quota": null
}

# Unset organization-specific quota
PATCH /api/v2/organizations/{id}
{
  "token_quota": null
}

For implementation examples, refer to the Go SDK usage guide:
🔗 https://github.com/auth0/go-auth0/blob/main/EXAMPLES.md#providing-a-custom-user-struct

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📚 References

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🔬 Testing

• Unit tests cover all new structs and unmarshal/marshal behaviour
• Manual tests verified PATCH operations unset values correctly
• Validated behavior with realistic tenant, client, and org payloads

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📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.84%. Comparing base (f54fa8c) to head (16d6cfa).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #537      +/-   ##
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+ Coverage   95.82%   95.84%   +0.01%     
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  Files          60       60              
  Lines       11639    11690      +51     
==========================================
+ Hits        11153    11204      +51     
  Misses        366      366              
  Partials      120      120              

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[Copilot]

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

[kushalshit27]

It would better to add implementation examples along with unset examples