Fix conformance gaps: exception types, byte/getBytes, host classes

Shake-out from the conformance-library sweep. Host-side fixes (runtime .ss,
no re-mint) plus one analyzer change (re-minted):

- Exception fidelity: ex-info and host-constructed throwables (RuntimeException.
  etc.) now carry their JVM class, so (class e), instance? across the exception
  hierarchy, .getMessage, and clojure.test thrown?/thrown-with-msg? all work.
- .getBytes returns a seqable/countable byte-array and honors UTF-16/UTF-32;
  String. decodes them. ->bytevector accepts byte-arrays (Base64).
- Universal .getClass / .toString / .indexOf / .lastIndexOf on any value/seq.
- record? uses the host jrec? predicate (the old (get x :jolt/deftype) crashed
  on a sorted-map by invoking its comparator).
- extend-protocol to abstract host types (clojure.lang.Fn/IFn/APersistentVector,
  java.net.URI) dispatches.
- New host classes: clojure.lang.PersistentQueue, java.util.ArrayList,
  java.net.URI, java.io.File / java.util.UUID ctors, Double/Float ctors+statics,
  regex instance? Pattern, System/setProperty.
- *assert* / *print-readably* are real settable/bindable vars.
- (symbol "ns/name") splits the namespace at the last slash.
- letfn fn params desugar destructuring (analyzer; re-minted).

unit.edn gains exinfo/hostobj/queue/hostctor/destructure regression rows.

host/chez/post-prelude.ss

@@ -97,3 +97,7 @@
 ;; chunked-seq? is true for a vector's seq (a real chunked-seq); the overlay's
 ;; always-false stub loaded over the host fn, so re-assert it (jolt-hs5q).
 (def-var! "clojure.core" "chunked-seq?" na-chunked-seq?)
+;; record? is a host type check (jrec?), not the overlay's (some? (get x
+;; :jolt/deftype)) — the get-trick invokes a sorted-map's comparator on
+;; :jolt/deftype and throws (jolt-3bbj). Matches the JVM (instance? IRecord).
+(def-var! "clojure.core" "record?" (lambda (x) (jrec? x)))