Increase DefaultJWTMaxTokenAge from 5 to 10 minutes to accommodate
identity providers like Azure Entra ID that backdate the iat claim
by up to 5 minutes, causing tokens to be immediately rejected.
Fixes#5449
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* **New Features**
* SSH server JWT validation now accepts multiple audiences with backward-compatible handling of the previous single-audience setting and a guard ensuring at least one audience is configured.
* **Tests**
* Test suites updated and new tests added to cover multiple-audience scenarios and compatibility with existing behavior.
* **Other**
* Startup logging enhanced to report configured audiences for JWT auth.
