core.async: higher-level API over native channels + two general fixes

Adds clojure.core.async's higher-level dataflow API as a Clojure overlay
(stdlib/clojure/core/async.clj) over jolt's native channel primitives, plus
clojure.core.async.lab. The native layer (host/chez/java/async.ss) gains
offer!/poll!, put specs and :priority/:default in alts!, a transducer
ex-handler arg to chan, unblocking-buffer?, promise-buffer, and on-caller?
handling for put!/take!. The overlay covers alts!/pipe/pipeline/split/
reduce/transduce/into/take/mult/mix/pub-sub/map/merge/onto-chan/to-chan and
the deprecated map</map>/filter>/... family (rewritten as go-loops since the
JVM versions reify the impl handler protocol jolt doesn't expose).

Loading: the native primitives pre-seed clojure.core.async, so the loader now
drops it from the loaded set and a require pulls the overlay from the source
roots like clojure.test (AOT-bundled into built binaries).

Running clojure/core.async's own suite shook out two general bugs:
- :refer with a list form, (:require [ns :refer (a b c)]), dropped the names
  (only the vector form was handled) — chez-register-spec! now accepts both.
- (range 0) / (range 5 5) returned nil instead of the empty seq () — empty
  ranges now match Clojure, so (= () (range 0)) holds.

Suite: async_test 15/20, pipeline_test 7/7, timers_test 2/2, lab_test 2/2.
The five non-passing async_test cases all assert JVM go-machine limitations
jolt's thread-based model is a superset of (the 1024 pending-op cap, parking
ops that must throw outside a go block, expanding-transducer buffer
backpressure) or dispatch-thread identity, not data semantics.

make test green (0 new divergences, +4 range corpus rows), shakesmoke
byte-identical.

docs/libraries.md

@@ -48,6 +48,10 @@ e.g. the [ring-app example](https://github.com/jolt-lang/examples/tree/main/ring
   [data.priority-map](https://github.com/clojure/data.priority-map).
 * [core.memoize](https://github.com/clojure/core.memoize) — function memoization
   over [core.cache](https://github.com/clojure/core.cache).
+* [core.async](https://github.com/clojure/core.async) — CSP channels and `go` blocks
+  (`<!`/`>!`/`alts!`, `pipeline`, `mult`/`mix`/`pub`/`sub`) on real OS threads.
+* [core.logic](https://github.com/clojure/core.logic) — relational logic programming
+  (unification, `run`/`fresh`/`conde`, finite domains).
 * [tick](https://github.com/juxt/tick) — date/time over Jolt's `java.time`;
   `#time/…` literals via `time-literals`.
 * [transit-jolt](https://github.com/jolt-lang/transit-jolt) — Transit (JSON) read/write