standardize authentication context extraction

Always use the standardized authtypes.ClaimsFromContext method for extracting authentication claims from request context, and handle errors properly. This ensures consistent authentication handling across the codebase and prevents potential security vulnerabilities from incorrect claim extraction.

The correct pattern is:

claims, err := authtypes.ClaimsFromContext(r.Context())
if err != nil {
    render.Error(rw, err)
    return
}

Avoid custom claim extraction methods or incorrect error handling patterns like claims, ok := authtypes.ClaimsFromContext(r.Context()) followed by if ok != nil - this can lead to authentication bypasses if the error handling logic is inverted. Using the standardized method ensures proper error propagation and consistent security behavior across all handlers.