Track :refer-clojure :exclude so syntax-quote qualifies an excluded name to the current ns

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.

host/chez/host-contract.ss

@@ -326,6 +326,10 @@
           ;; Referred names live in a separate table, so this only hits a real
           ;; local intern, matching how the analyzer resolves the bare symbol.
           ((var-cell-lookup (chez-actx-cns ctx) nm) (jolt-symbol (chez-actx-cns ctx) nm))
+          ;; a name the compile ns excluded from clojure.core (:refer-clojure
+          ;; :exclude) is not clojure.core/nm even before the ns defines its own —
+          ;; qualify to the compile ns, like Clojure (core.logic.fd's `==`).
+          ((chez-core-excluded? (chez-actx-cns ctx) nm) (jolt-symbol (chez-actx-cns ctx) nm))
           ((var-cell-lookup "clojure.core" nm) (jolt-symbol "clojure.core" nm))
           ;; a name referred into the compile ns (:require :refer / :use :only)
           ;; qualifies to its SOURCE ns, not the compile ns — so a macro that