Auto-resolve ::keywords; honor clojure.edn reader opts

The reader dropped the namespace on ::kw (read ::foo as :foo), so auto-resolved
keywords never matched their qualified form — code that round-trips them (spec
keys, aero's :aero.core/* expansion keys) silently broke. Resolve ::name against
the current ns and ::alias/name through the alias table, as Clojure does. The
runtime loader reads form-by-form with the ns set after the ns form; the
cross-compile reads all forms up front, so ei-emit-ns*/ei-emit-ns-records set the
ns before reading.

clojure.edn/read over a reader discarded its opts map — :readers/:default/:eof
were ignored, so a custom :default never saw the tag. Route the reader arity
through read-string so opts apply, and pass the tag to :default as a symbol (not
the internal :#name keyword), matching Clojure.

Seed re-minted (the ::halt transducer key in clojure.core now reads as
:clojure.core/halt). Corpus gains ::-keyword rows; the unit case that asserted the
old ns-dropping behavior now asserts the qualified result.

host/chez/emit-image.ss

@@ -59,6 +59,10 @@
 ;; that fails to emit) and `jolt build` (bld-emit-ns: optimize? #t, guard? #f —
 ;; strict, a failing form errors the build).
 (define (ei-emit-ns* ns-name src optimize? guard?)
+  ;; set the ns before reading so ::kw auto-resolves against this ns (the runtime
+  ;; loader reads form-by-form after the ns form sets it; the cross-compile reads
+  ;; all forms up front, so set it here).
+  (set-chez-ns! ns-name)
   (let loop ((forms (ei-read-all src)) (acc '()))
     (if (null? forms)
         (reverse acc)
@@ -92,6 +96,7 @@
 ;; record whose refs are roots. A macro is prunable — its expander isn't called at
 ;; runtime in an AOT build.
 (define (ei-emit-ns-records ns-name src)
+  (set-chez-ns! ns-name)               ; ::kw resolves against this ns (see ei-emit-ns*)
   (let loop ((forms (ei-read-all src)) (acc '()))
     (if (null? forms)
         (reverse acc)