Chez numeric tower: exact ints / Ratio / double for JVM parity (jolt-n6al)

jolt was all-flonum (one :number type, inherited from Janet whose only number
type is a double). The Chez runtime has a full numeric tower, so the zero-Janet
path now carries it = JVM Clojure semantics:

  (/ 1 2)      => 1/2      (exact Ratio, was 0.5)
  (integer? 3) => true   (integer? 3.0) => false   (float? 3.0) => true
  (ratio? (/ 1 2)) => true   (= 3 3.0) => false   (== 3 3.0) => true
  (+ 1 2) => 3 (exact)   (/ 1.0 2) => 0.5 (double)

jolt= was already exactness-aware (values.ss) and == is value-equality, so
=/== match the JVM split. The reader preserves exactness (integer literals exact,
a/b ratios exact rationals, decimals/exponents flonums); backend_scheme emit-const
renders exact ints/ratios and flonums faithfully; the value-position arithmetic,
count, int, compare, bit ops, parseLong, string .length/.indexOf, range,
timestamps, and array bytes return exact integers (= JVM int/long) instead of
coercing to flonum. double/parseDouble/clojure.math floor|ceil|signum stay double.

Only the zero-Janet path carries the tower (the Janet reader loses exactness into
a double before emit). The prelude/all-flonum path is unaffected for compiled code;
the runtime reader is shared, so a couple of all-flonum reader assertions become
value (==) assertions. ~16 numeric corpus cases now give the JVM tower value vs the
Janet-era :expected and are allowlisted as tower divergences (Chez == reference
JVM) pending the corpus flip to JVM (jolt-ecz0). No BigDecimal type (1M).

Re-minted. zero-janet 2682 (floor 2698->2682, the reclassified tower cases), 0 new
divergences; fixpoint 10/10, bootstrap 6/6, spine 35/35, cli 49/49; Janet gate 155
files 0 failed.

host/chez/predicates.ss

@@ -22,8 +22,16 @@
 (define (jolt-number? x) (number? x))
 (define (jolt-string? x) (string? x))
 (define (jolt-char-pred? x) (char? x))
-;; finite integral number — Chez integer? already rejects the infinities and NaN.
-(define (jolt-integer? x) (and (number? x) (integer? x)))
+;; JVM-parity number-type predicates over the Chez numeric tower. integer? is the
+;; INTEGER TYPE (exact integer = Long/BigInt), NOT integer-VALUED: (integer? 3.0)
+;; is false on the JVM (3.0 is a Double). float? = flonum (double). ratio? = exact
+;; non-integer (= JVM Ratio). rational? = exact (integer or ratio; jolt has no
+;; BigDecimal). decimal? is always false (no BigDecimal type).
+(define (jolt-integer? x) (and (number? x) (exact? x) (integer? x)))
+(define (jolt-float? x) (and (number? x) (flonum? x)))
+(define (jolt-ratio? x) (and (number? x) (exact? x) (rational? x) (not (integer? x))))
+(define (jolt-rational? x) (and (number? x) (exact? x)))
+(define (jolt-decimal? x) #f)
 (define (jolt-fn? x) (procedure? x))
 (define (jolt-boolean-pred? x) (boolean? x))
 
@@ -50,6 +58,20 @@
 (def-var! "clojure.core" "string?" jolt-string?)
 (def-var! "clojure.core" "char?" jolt-char-pred?)
 (def-var! "clojure.core" "integer?" jolt-integer?)
+(def-var! "clojure.core" "float?" jolt-float?)
+(def-var! "clojure.core" "ratio?" jolt-ratio?)
+(def-var! "clojure.core" "rational?" jolt-rational?)
+(def-var! "clojure.core" "decimal?" jolt-decimal?)
+;; == numeric value-equality (ignores exactness, unlike =): (== 3 3.0) -> true.
+;; 1-arity is trivially true; 2+ args must all be numbers (Numbers.equiv throws
+;; otherwise). Uses Scheme = (value across the tower), not jolt= (category-aware).
+(define (jolt-num-equiv . xs)
+  (let all-num? ((ys xs))
+    (cond
+      ((null? ys) (or (null? xs) (null? (cdr xs)) (apply = xs)))
+      ((number? (car ys)) (all-num? (cdr ys)))
+      (else (error #f "== requires numbers" xs)))))
+(def-var! "clojure.core" "==" jolt-num-equiv)
 (def-var! "clojure.core" "symbol?" jolt-symbol?)
 (def-var! "clojure.core" "keyword?" keyword?)
 (def-var! "clojure.core" "map?" jolt-map?)