Scope must be a space-delimited string per RFC 6749 §3.3, not a JSON
array. Adds [] and ["openid","profile"] cases to the existing invalid
sub-test with a comment explaining the likely root cause: an issuer
using []string instead of SpaceDelimited in its claims struct.
Distinguishes the two validator constructors by signature:
- NewIDTokenValidator(iss, aud, azp []string) — allowlist semantics
- NewAccessTokenValidator(iss, aud []string, requiredScopes ...string) — requirement semantics
Variadic scopes read naturally at the call site:
NewAccessTokenValidator(issuers, audiences, "openid", "profile")
Three-state semantics preserved:
no args → scope not checked
[]string{}... → scope must be present (any value)
"openid", ... → scope must contain all listed values
Also removes the old gracePeriod parameter from both constructors
(was 0 at all call sites; set GracePeriod on the struct directly
if a non-default value is needed).
Adds TestCov_NewAccessTokenValidator_Scopes covering all three cases.
