A name a namespace excludes from clojure.core (:refer-clojure :exclude) is not
clojure.core/name even before the ns defines its own — syntax-quote must qualify
it to the current ns, like Clojure. refer-clojure was a no-op, so a syntax-quoted
excluded name (core.logic.fd's `==`, referenced by a constraint's -rator before fd
defines ==) resolved to clojure.core/==.
jolt-refer-clojure now records the :exclude set per ns; hc-sq-symbol consults it
before falling back to clojure.core. Fixes core.logic's fd constraint -rator names.
Runtime only, no re-mint.