Run core.memoize's test suite on jolt

Shaking out clojure.core.memoize (207 assertions, 0 fail) cleared several
general gaps:

- deref/@ on a deftype or reify implementing clojure.lang.IDeref dispatches to
  its deref method (RetryingDelay / make-derefable).
- deftype mutable fields (^:unsynchronized-mutable / ^:volatile-mutable) are
  read live: a set! within a method is observed by a later read in the same
  invocation, not the entry-time capture. Needed for double-checked locking.
  Immutable fields stay let-bound. Field reads rewrite to (.-field inst) with
  lexical-shadow tracking.
- def metadata values are evaluated, like Clojure: ^{:k (f)} stores (f)'s
  result and ^{:af some-fn} the fn. :tag stays a literal hint.
- try dispatches catch clauses by class in order via the exception supertype
  hierarchy; a non-matching value re-throws, an untyped host condition is caught
  by a RuntimeException/Exception/Throwable clause. Previously the last clause
  won and the class was ignored.
- locking takes a real per-object monitor (recursive Chez mutex) now that
  futures/agents/threads share one heap; it was a no-op.
- supers/ancestors reflect a small modeled JVM interface hierarchy, so
  (ancestors (class f)) yields Runnable/Callable (core.memoize's arg check).
- AssertionError / Error constructors.

JOLT_FEATURES is gone from the docs: it isn't read anywhere on Chez, and the
reader already includes :clj in its default feature set. RFC 0002's
{:jolt :default} design was reverted in the reader; docs now match the code.

Raises the SCI floor 205 -> 210.

host/chez/run-sci.ss

@@ -1,11 +1,11 @@
 ;; run-sci.ss — SCI conformance: load borkdude/sci's own source (vendor/sci) through
 ;; joltc and require its forms to compile+eval. A real-world Clojure-compatibility
 ;; stress test. Floor-gated like the corpus: a regression below
-;; the floor (or the count today, 205/218) fails. Raise the floor as host gaps close
+;; the floor (or the count today, 210/218) fails. Raise the floor as host gaps close
 ;; (the tail is genuine gaps — set! on vars, some macro/def shapes).
 ;;
 ;;   chez --script host/chez/run-sci.ss
-;;   JOLT_SCI_FLOOR=N    override the floor (default 205)
+;;   JOLT_SCI_FLOOR=N    override the floor (default 210)
 ;;   SCI_VERBOSE=1       print each failing form's error
 (import (chezscheme))
 
@@ -74,7 +74,7 @@
   load-order)
 
 (printf "\nSCI load: ~a/~a forms ok (~a fail)\n" total-ok (+ total-ok total-fail) total-fail)
-(define floor (let ((s (getenv "JOLT_SCI_FLOOR"))) (if s (string->number s) 205)))
+(define floor (let ((s (getenv "JOLT_SCI_FLOOR"))) (if s (string->number s) 210)))
 (when (< total-ok floor)
   (printf "REGRESSION: ~a forms loaded < floor ~a\n" total-ok floor))
 (flush-output-port)