Host completeness for clj-http-lite: with-open/slurp on shims, charset, exc classes

Gaps the clj-http-lite suite hit running over jolt-lang/http-client:

- with-open now closes a tagged-table stream shim via its .close method (was a
  :close field lookup that only matched the Janet-era tables).
- slurp accepts a bytevector / jolt byte-array / a byte input-stream shim and
  honors :encoding — clj-http-lite slurps response bodies and :as :stream bodies.
- (.getBytes s charset) and Charset/forName respect the charset (ISO-8859-1 etc.,
  one byte per char), not always UTF-8; Charset/forName returns the name string.
- (class e) reads the JVM :class off a throwable tagged-table, so clojure.test's
  (thrown? Class …) / (= Class (class e)) match a library's typed exceptions.
- Registered the HTTP/IO exception class names (IOException, UnknownHostException,
  SocketTimeoutException, SSLException, …) so the FQ literals self-evaluate.

All runtime .ss shims, no re-mint. Full gate green.

host/chez/host-static.ss

@@ -583,7 +583,9 @@
     (let loop ((l lst) (i 0)) (if (null? l) bv (begin (bytevector-u8-set! bv i (car l)) (loop (cdr l) (+ i 1)))))))
 (register-class-statics! "URLEncoder" (list (cons "encode" url-encode)))
 (register-class-statics! "URLDecoder" (list (cons "decode" url-decode)))
-(register-class-statics! "Charset" (list (cons "forName" (lambda (nm) (make-jhost "charset" (list (cons 'name nm)))))))
+;; Charset/forName yields the canonical name STRING (not an opaque object) so it
+;; threads straight into (.getBytes s cs) / (String. bytes cs), which take a name.
+(register-class-statics! "Charset" (list (cons "forName" (lambda (nm) (jolt-str-render-one nm)))))
 
 ;; ---- Base64 (RFC 4648) ------------------------------------------------------
 (define b64-alphabet "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")