MIGRATION_A365.md uses old observability scope — needs update to new OtelWrite scope

[fpfp100]

Summary

The migration guide's AgenticTokenCache custom instance example still uses the old Power Platform scope. The scope for the ingestion service has changed but this is not mentioned anywhere in the migration guide.

Bug

In MIGRATION_A365.md section 6 — Custom instance:

const tokenCache = new AgenticTokenCache({
  authScopes: ["https://api.powerplatform.com/.default"],
});

This uses the old scope. The correct scopes are:

Auth flow	New scope
OBO (on-behalf-of)	api://9b975845-388f-4429-889e-eab1ef63949c/Agent365.Observability.OtelWrite
S2S (service-to-service)	api://9b975845-388f-4429-889e-eab1ef63949c

Ask

1. Update the AgenticTokenCache example to use the correct new scope
2. Add a migration step documenting the scope change — this is a breaking change that users need to know about
3. A365 SDK provide public method to retreive scope for OBO. This should continue to be supported.

References

• Migration guide: https://github.com/microsoft/opentelemetry-distro-javascript/blob/main/MIGRATION_A365.md
• Scope requirement documented in docs: agent365-docs/developer/microsoft-opentelemetry.md (HTTP 403 section)

[github-actions]

cc @hectorhdzg @JacksonWeber @lzchen @MSNev @rads-1996 @jeremydvoss