Webhook for generate JWT access token and ID token

**Problem**
Users are required to have custom JWT claims/namespaces, for some gateway or serverless services (e.g. [Hasura](https://hasura.io/docs/latest/auth/authentication/jwt/))

**Appetite**
4 weeks

**Solution**
Include two new webhook for generate JWT access token, or ID tokens.

**Rabbit holes**
Details about the solution worth calling out to avoid problems

**No-goes**
Functionality or use cases we intentionally aren’t covering to fit the appetite

Start by locating the existing JWT access-token and ID-token generation paths and webhook integration in the Go repository. Define the two webhook contracts, including custom JWT claims or namespaces, and add coverage for both token types; done means the generated tokens support the stated gateway or serverless use case.

Written by the indexing model from the issue text.