Cross-ns def/require/use/defmethod through the spine (jolt-c2l1)

The per-form eval passed a FIXED compile-ns to every subform of a top-level do,
so a runtime (ns ...)/(in-ns ...) didn't redirect later defs/refs — defs landed
in the wrong ns and qualified refs hit host-static ("Unknown class"). Thread
the current ns: each subform analyzes in (chez-current-ns), which ns/in-ns move.

That exposed two more gaps, now fixed:
- use refers ALL of a target's public vars (a refer-all table consulted by
  chez-resolve-refer) — was bound to plain require (explicit :refer only).
- defmethod on a QUALIFIED multifn (cf.mm/ext from another ns) resolves in the
  symbol's ns, not the current one (was auto-creating a stray multifn).

Corpus 2684->2688, 0 new divergences; floor raised. No re-mint (runtime shims).

host/chez/run-unit.ss

@@ -55,6 +55,7 @@
   (zj-prune! type-registry zj-type-base)
   (hashtable-clear! ns-alias-table)
   (hashtable-clear! ns-refer-table)
+  (hashtable-clear! ns-refer-all-table)
   (when zj-ghier (jolt-invoke (var-deref "clojure.core" "reset!")
                    (var-cell-root zj-ghier) (jolt-invoke (var-deref "clojure.core" "make-hierarchy"))))
   (set-chez-ns! "user"))