Group the secrets import with time and webbrowser at the top of
run_hermes_oauth_login_pure(), matching the existing pattern.
Drop the _secrets alias — no name conflict in this scope.
The PKCE flow reused the code_verifier as the OAuth state parameter.
Per RFC 6749 §10.12 and RFC 7636, these serve different purposes:
state is an anti-CSRF token visible in the authorization URL; the
code_verifier must remain secret for the token exchange.
Generate an independent secrets.token_urlsafe(32) for state and
validate it on callback to provide actual CSRF protection.
Closes#10693