test(08-07): add failing RED anchor for fonoteka:oauth-client command

- TestPhase8RedOAuthClientCommand drives the not-implemented command
  stub's create path and fails with PHASE8_RED:oauth-command until the
  real create/update/list behavior lands (D-19)
- oauth_client.go stub declares the exact PHP-parity flag/argument
  contract (name, --redirect-uri=*, --scope=*, --auth-method,
  --client-id, --list) so the RED test exercises the real command shape
- user/console_test.go's emailArg gains Flags(string) []string: bonfire's
  Input interface (summercms.go) grew this method for D-19's repeatable
  flags, and emailArg must satisfy it to keep building

console_test.go

@@ -52,3 +52,5 @@ func (e emailArg) Argument(name string) (string, bool) {
 }
 
 func (e emailArg) Flag(string) (string, bool) { return "", false }
+
+func (e emailArg) Flags(string) []string { return nil }