Point an OIDC authorization-code flow's redirect_uri at this host. On callback,
this Worker exchanges the code for tokens (public client, no secret) and shows the
decoded token.
https://redirect-test.contenthub.dev/callback
https://auth.alturos.com/auth/realms/corp/protocol/openid-connect/auth?client_id=james-cli&redirect_uri=https%3A%2F%2Fredirect-test.contenthub.dev%2Fcallback&response_type=code&scope=openid+profile+email&state=1
Override the client with ?client_id= on the redirect URI.