Refactor API to use IOptions pattern with IConfigurationSection binding

[kailash-b]

✏️ Changes

This PR refactors the public API surface to adopt the ASP.NET Core IOptions pattern with IConfigurationSection binding, replacing the previous approach of eagerly-evaluated Action<Auth0ApiOptions> callbacks that required users to manually wire JwtBearerOptions inside Auth0ApiOptions.

Added:

• Auth0ApiOptionsValidator — validates Domain is set via IValidateOptions<Auth0ApiOptions>
• Auth0JwtBearerConfigureOptions — implements IConfigureNamedOptions<JwtBearerOptions> to resolve Auth0ApiOptions at options resolution time (not registration time)
• Auth0JwtBearerOptionsValidator — validates audience is configured on the final JwtBearerOptions, supporting both single-audience and multi-audience (ValidAudiences) scenarios
• New ServiceCollectionExtensions overloads accepting IConfigurationSection for direct appsettings.json binding

Modified:

• Auth0ApiOptions — simplified to contain only Domain and Audience (removed JwtBearerOptions property)
• Auth0ApiAuthenticationBuilder — no longer holds Auth0ApiOptions instance; stores only AuthenticationScheme and Services
• AuthenticationBuilderExtensions — replaced Action<Auth0ApiOptions> parameter with Action<JwtBearerOptions>? configureJwtBearer; removed manual property copying in ConfigureJwtBearerOptions
• JwtBearerEventsFactory / DPoPEventsFactory — now accept JwtBearerEvents? directly instead of Auth0ApiOptions
• ServiceCollectionExtensions — delegate overloads now register options via services.Configure<Auth0ApiOptions> and delegate to the AuthenticationBuilder-based extension

Removed:

• ConfigureJwtBearerOptions method (manual property-by-property copy)
• ValidateAuth0ApiOptions method (replaced by IValidateOptions implementations)
• WithDPoP overloads accepting authenticationScheme parameter (uses builder.AuthenticationScheme instead)

New public API usage:

// Configuration-section binding (recommended)
builder.Services.AddAuth0ApiAuthentication(
    builder.Configuration.GetSection("Auth0"),
    configureJwtBearer: jwt => { /* customize JwtBearerOptions */ }
).WithDPoP();

// Delegate-based
builder.Services.AddAuth0ApiAuthentication(
    options => { options.Domain = "tenant.auth0.com"; options.Audience = "https://api"; },
    configureJwtBearer: jwt => { /* customize */ }
);

🔗 References

🎯 Testing

• This change adds unit test coverage

• This change adds integration test coverage

• This change has been tested on the latest version of the platform/language or why not

✅ Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

• All commits are signed.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.62500% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.67%. Comparing base (79dd413) to head (ade7c9b).

Files with missing lines	Patch %	Lines
...thentication.Api/Auth0JwtBearerConfigureOptions.cs	86.36%	3 Missing ⚠️
...uthentication.Api/Auth0ApiAuthenticationBuilder.cs	33.33%	2 Missing ⚠️
...thentication.Api/Auth0JwtBearerOptionsValidator.cs	95.83%	0 Missing and 1 partial ⚠️
...hentication.Api/AuthenticationBuilderExtensions.cs	97.22%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #59      +/-   ##
==========================================
+ Coverage   92.12%   92.67%   +0.55%     
==========================================
  Files          26       29       +3     
  Lines        1358     1433      +75     
  Branches      154      164      +10     
==========================================
+ Hits         1251     1328      +77     
- Misses         75       76       +1     
+ Partials       32       29       -3     

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