Pure-Chez test gates (no Janet)

Add a Janet-free gate so correctness can be judged with only Chez + Clojure:
- host/chez/run-corpus.ss: corpus.edn vs JVM expecteds, lifting the per-case ns
  isolation from the old Janet driver; reads corpus.edn via the jolt reader.
- host/chez/run-unit.ss + test/chez/unit.edn: the host-specific unit cases,
  evaluated in-process and compared to baked expecteds.
- host/chez/selfcheck.sh: self-host fixpoint (bootstrap.ss rebuild == checked-in seed).
- host/chez/smoke.sh: real bin/joltc CLI smoke.
- host/chez/remint.sh: re-mint the seed to a byte-fixpoint after a source change.
- Makefile: 'make test' runs the lot; 'make remint' rebuilds the seed.

Numbers match the Janet gate: corpus 2679/2757 0 new div, unit 450/450, certify
0 new/0 stale.

jolt-cf1q.6

host/chez/remint.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+# Re-mint the checked-in Chez seed. Run after changing a seed source — the reader
+# (host/chez/reader.ss), the analyzer/IR/backend (jolt-core/jolt/*.clj), or the
+# clojure.core overlay (jolt-core/clojure/core/*.clj). Iterates bootstrap.ss from the
+# current seed to a byte-fixpoint and overwrites host/chez/seed/.
+set -e
+root="$(CDPATH= cd -- "$(dirname -- "$0")/../.." && pwd)"
+cd "$root"
+tmp="$(mktemp -d)"
+trap 'rm -rf "$tmp"' EXIT
+
+cp host/chez/seed/prelude.ss "$tmp/cur-p.ss"
+cp host/chez/seed/image.ss   "$tmp/cur-i.ss"
+i=0
+while [ "$i" -lt 8 ]; do
+  i=$((i + 1))
+  chez --script host/chez/bootstrap.ss \
+    "$tmp/cur-p.ss" "$tmp/cur-i.ss" "$tmp/new-p.ss" "$tmp/new-i.ss" >/dev/null
+  if diff -q "$tmp/cur-p.ss" "$tmp/new-p.ss" >/dev/null \
+     && diff -q "$tmp/cur-i.ss" "$tmp/new-i.ss" >/dev/null; then
+    cp "$tmp/new-p.ss" host/chez/seed/prelude.ss
+    cp "$tmp/new-i.ss" host/chez/seed/image.ss
+    echo "re-minted seed (converged after $i pass(es))"
+    exit 0
+  fi
+  cp "$tmp/new-p.ss" "$tmp/cur-p.ss"
+  cp "$tmp/new-i.ss" "$tmp/cur-i.ss"
+done
+echo "re-mint did not converge in 8 passes" >&2
+exit 1