* feat: make upstream_client_secret optional in OAuthProxy
Extract _create_upstream_oauth_client() factory method for subclass
override. Cookie signing falls back to JWT key material when no secret.
* fix: include client_id in revocation requests for public clients
* fix: use factory method for revocation auth
* Checkpoint progress
* Checkpoint progress
* add derive b64 method
* PR clean-up
* refactor da proxy
* Updates to tests
* Make jwt_signing_key required for oauth proxy
* use typing_extensions and fix tests
* PR Cleanup
* also adjust integration tests
* Update docs, use client secret to derive jwt signing key
* You win some you lose some, gg claude
* check for both in derive
* update documentation / clean up
* Update http.mdx
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Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>