Add documentation for the new SignalR authentication refresh feature, which lets a
connected client update its authentication credentials for an active connection without
reconnecting.

- authn-and-authz.md: Add an "Authentication refresh" section (gated to .NET 11) covering
  how to enable it on the server, refresh from the .NET and JavaScript clients, and react
  to a refresh in the hub. Cross-link the "User and role changes" section.
- configuration.md: Document the new HttpConnectionDispatcherOptions members
  (EnableAuthenticationRefresh, MaximumAuthenticationExpiration, OnAuthenticationRefresh)
  in the advanced HTTP options.
- client-features.md: Add an "Authentication Refresh" row to the client feature matrix.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Bumps [brace-expansion](https://github.com/juliangruber/brace-expansion) from 1.1.12 to 1.1.18.
- [Release notes](https://github.com/juliangruber/brace-expansion/releases)
- [Commits](juliangruber/brace-expansion@v1.1.12...v1.1.18)

---
updated-dependencies:
- dependency-name: brace-expansion
  dependency-version: 1.1.18
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>