Group the JVM interop shims under host/chez/java/

The host/chez directory mixed jolt's own runtime (value model, seq, reader,
vars, ns, multimethods) with the shims that emulate the JVM: java.* / javax.*
classes, clojure.lang interfaces, and the host-class registry they hang off.
Move that JVM-emulation layer into host/chez/java/ so it reads as a distinct
unit instead of being interleaved with the platform runtime.

Moved (content unchanged): host-static, host-static-methods,
host-static-classes, host-class, dot-forms, records-interop, byte-buffer,
io, io-streams, inst-time, java-time, bigdec, natives-queue, natives-str,
natives-array, math, concurrency, async, ffi.

The load paths in rt.ss/cli.ss and the build.ss runtime manifest are updated
to point at java/; the build inliner follows the (load ...) strings, so the
AOT path needs no other change. All runtime shims, no seed source touched
(the three .clj edits are doc comments), so no re-mint.

Gate green: make test (selfhost fixpoint, certify 0-new, sci 211, infer),
shakesmoke (4 apps byte-identical).

host/chez/build.ss

@@ -111,7 +111,7 @@
     'compile-eval
     "(load \"host/chez/png.ss\")"
     "(load \"host/chez/loader.ss\")"
-    "(load \"host/chez/ffi.ss\")"
+    "(load \"host/chez/java/ffi.ss\")"
     "(set-source-roots! (list \"jolt-core\" \"stdlib\"))"))
 
 (define bld-tagged-loads

host/chez/cli.ss

@@ -24,7 +24,7 @@
 ;; jolt.ffi host primitives (memory / library loading) load AFTER the loader's
 ;; baked-ns snapshot, so a library's (require '[jolt.ffi]) still loads jolt.ffi's
 ;; Clojure side (the foreign-fn / defcfn macros, stdlib/jolt/ffi.clj).
-(load "host/chez/ffi.ss")          ; jolt.ffi (FFI: a library binds native code)
+(load "host/chez/java/ffi.ss")          ; jolt.ffi (FFI: a library binds native code)
 
 ;; jolt.main + jolt.deps live under jolt-core; keep them (and stdlib) on the
 ;; roots so the CLI's own namespaces — and any jolt.* an app pulls in — resolve.

host/chez/rt.ss

@@ -259,7 +259,7 @@
 ;; the dispatchers/printers it wraps (collections/seq/values/converters/printing/
 ;; transients).
 (load "host/chez/records.ss")
-(load "host/chez/records-interop.ss")   ; exception hierarchy + instance-check taxonomy
+(load "host/chez/java/records-interop.ss")   ; exception hierarchy + instance-check taxonomy
 
 ;; metadata: meta / with-meta over an identity-keyed
 ;; side-table. After records.ss (jrec) + the collection ctors it copies.
@@ -268,7 +268,7 @@
 ;; host class tokens: bare class names (String/Keyword/File...) ->
 ;; canonical JVM class-name strings + (class x). After natives-meta.ss (jolt-type)
 ;; and the printer (jolt-str-render-one).
-(load "host/chez/host-class.ss")
+(load "host/chez/java/host-class.ss")
 
 ;; dynamic vars: *clojure-version* / *unchecked-math* constants the host
 ;; binds natively. After collections.ss (jolt-hash-map) + def-var!.
@@ -324,39 +324,39 @@
 ;; portable String/CharSequence surface record-method-dispatch falls through to on
 ;; a string target. After regex.ss (jolt-re-pattern/regex-t-irx) + records.ss
 ;; (which references jolt-string-method).
-(load "host/chez/natives-str.ss")
+(load "host/chez/java/natives-str.ss")
 
 ;; host class statics + constructors: host-static-ref/
 ;; host-static-call/host-new + the jhost method registry. Loads LAST — it extends
 ;; record-method-dispatch (records.ss) and reuses natives-str helpers (str-trim,
 ;; ascii-string-down, re-split, str-split-drop-trailing) + the regex-t accessors.
-(load "host/chez/host-static.ss")          ; registries + jhost + coercion helpers
-(load "host/chez/host-static-methods.ss")  ; Class/member static methods + fields
-(load "host/chez/host-static-classes.ss")  ; instantiable host object classes
-(load "host/chez/byte-buffer.ss")          ; java.nio.ByteBuffer over a byte-array
+(load "host/chez/java/host-static.ss")          ; registries + jhost + coercion helpers
+(load "host/chez/java/host-static-methods.ss")  ; Class/member static methods + fields
+(load "host/chez/java/host-static-classes.ss")  ; instantiable host object classes
+(load "host/chez/java/byte-buffer.ss")          ; java.nio.ByteBuffer over a byte-array
 
 ;; generic dot-form dispatch: field access + map/vector member access
 ;; for the `.` / `.-field` desugar. Loads after host-static.ss so it wraps every
 ;; record-method-dispatch arm (jhost/number/regex/jrec/string) and falls through.
-(load "host/chez/dot-forms.ss")
+(load "host/chez/java/dot-forms.ss")
 
 ;; java.io.File + host file I/O: path-backed jfile record, slurp/spit/
 ;; flush, file-seq dir primitives, clojure.java.io/file. Loads LAST so its jfile
 ;; arm wraps the fully-built record-method-dispatch and the str/type/instance-check
 ;; extensions sit over every prior shim.
-(load "host/chez/io.ss")
+(load "host/chez/java/io.ss")
 
 ;; #inst values + java.time formatting: jinst (RFC3339 ms) +
 ;; DateTimeFormatter/Instant/ZoneId/LocalDateTime/FormatStyle/Locale/Date. Loads
 ;; LAST — it extends record-method-dispatch / jolt-get / jolt= / jolt-hash /
 ;; jolt-pr-str / jolt-type / instance-check and uses host-static.ss's registries.
-(load "host/chez/inst-time.ss")
+(load "host/chez/java/inst-time.ss")
 
 ;; java.time value types: LocalDate / LocalTime / LocalDateTime / Instant as
 ;; tz-free jhost values (epoch-day / nano-of-day / epoch-ms). Loads after
 ;; inst-time.ss — it reuses its civil<->days helpers, the jhost registries, and
 ;; re-registers a few LocalDateTime/Instant statics to use the richer reps.
-(load "host/chez/java-time.ss")
+(load "host/chez/java/java-time.ss")
 
 ;; Chez-side data reader: read-string / __parse-next /
 ;; __read-tagged. Loads after inst-time.ss — __read-tagged reuses its #uuid/#inst
@@ -365,7 +365,7 @@
 
 ;; clojure.math: native flonum-math shims def-var!'d into the
 ;; clojure.math ns. Self-contained (only def-var! + Chez math), order-independent.
-(load "host/chez/math.ss")
+(load "host/chez/java/math.ss")
 
 ;; reader/macro runtime support: #?() feature set, reader-conditional + re-matcher
 ;; tagged-map ctors, macroexpand. After ns.ss; macroexpand call-time-refs the macro
@@ -375,17 +375,17 @@
 ;; Java-style arrays: object/typed array constructors + a jolt-array
 ;; backing; extends count/nth/seq/get/ref-put! so the overlay aget/aset/alength see
 ;; it. After the dispatchers it chains.
-(load "host/chez/natives-array.ss")
+(load "host/chez/java/natives-array.ss")
 
 ;; java.io byte/char streams (FileInputStream/…/ByteArrayOutputStream/Buffered*)
 ;; over Chez ports. After io.ss (extends its slurp/__close/reader-jhost?) and
 ;; natives-array.ss (the byte-array <-> bytevector bridge).
-(load "host/chez/io-streams.ss")
+(load "host/chez/java/io-streams.ss")
 
 ;; clojure.lang.PersistentQueue: a functional queue + EMPTY static.
 ;; Chains seq/count/empty?/peek/pop/conj/sequential?/class/instance?/printer, so
 ;; load after natives-array (the dispatchers it extends).
-(load "host/chez/natives-queue.ss")
+(load "host/chez/java/natives-queue.ss")
 
 ;; syntax-quote form builders: __sqcat/__sqvec/__sqmap/__sqset/
 ;; __sq1, def-var!'d into clojure.core. A cross-compiled macro expander (analyzer
@@ -397,14 +397,14 @@
 ;; (JVM) semantics. Loaded LAST — chains the fully-built jolt-deref and conveys the
 ;; thread-local binding stack (dyn-binding.ss) into workers. pmap/pcalls/pvalues
 ;; (overlay, over `future`) light up once future-call exists here.
-(load "host/chez/concurrency.ss")
+(load "host/chez/java/concurrency.ss")
 
 ;; clojure.core.async: real-thread blocking channels + go/go-loop/
 ;; thread macros, def-var!'d into clojure.core.async. After concurrency.ss (reuses
 ;; ms->duration) and the collection/seq layer.
-(load "host/chez/async.ss")
+(load "host/chez/java/async.ss")
 
 ;; BigDecimal: the jbigdec value type + bigdec/decimal?/class/equality/
 ;; printing. Loads LAST so its set!-wraps of jolt-class/jolt=2/the printers sit
 ;; outermost over every earlier extension.
-(load "host/chez/bigdec.ss")
+(load "host/chez/java/bigdec.ss")