Clojure 1.13 parity: req!, checked-keys destructuring, keyword array maps

Bring the language up to the 1.13.0-alpha1 changes that apply off the JVM:

- req! (CLJ-2949): a get-variant that throws "Expected key: k" on a missing
  key, without nil-punning. The primitive behind checked destructuring.
- Checked-keys destructuring (CLJ-2961): :keys!/:syms!/:strs! bind and throw
  when a key is absent; keys after & are declared-only (required for the !
  variants, accepted otherwise) and create no binding.
- & is no longer a legal local binding in let/loop (CLJ-2954).
- Keyword-only array maps grow to 64 entries before going hash (was 8),
  across the literal, assoc, and transient paths, so the common keyword map
  keeps insertion order up to 64.

Skipped CLJ-2891 (JVM __init bytecode, JVM-only). 1.13 is still alpha, so
this tracks alpha1 and may shift. Regression tests in test/chez/unit.edn
(ahead of the JVM 1.12.5 the corpus certifies against). Seed re-minted.

host/chez/transients.ss

@@ -86,7 +86,11 @@
                (if (fx<? i cnt) (begin (vector-set! out i (vector-ref buf i)) (loop (fx+ i 1)))
                    (make-pvec out)))))))
     ((map)
-     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t)))
+     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t))
+            ;; Clojure 1.13: a keyword-only map stays an array map up to 64 entries,
+            ;; so a keyword map built through a transient (into {} …) keeps insertion
+            ;; order to 64, matching the literal/assoc paths.
+            (cap (if (all-keywords? (jolt-transient-ord t)) (fxmax array-map-limit-kw cap) cap)))
        (if (fx>? cnt cap)
            ;; promoted past the array capacity: hash order
            (let ((m empty-pmap-hash))