Host interop fixes: ==/time/subvec/defonce + corpus cleanup

- == 1-arg returns true for any value (Clojure short-circuits before the number
  check), not 'requires numbers'.
- current-time-ms wired to now-millis so the time macro works.
- subvec truncates float/ratio indices via long (Scheme quotient rejects flonums).
- defonce checks bound? not var-get — in a top-level do the name is already an
  unbound interned cell, which var-get throws on.
- drop the line-seq corpus row (used janet/spit, N/A); allowlist char-array
  (needs Class/forName "[C").

Corpus 2678->2683, floor raised. Re-minted. Full gate green; CI green.

jolt-cf1q.7

jolt-core/clojure/core/00-kernel.clj

@@ -27,12 +27,12 @@
   ([v start end]
    (when (not (vector? v)) (throw (str "subvec requires a vector")))
    ;; Clojure coerces indices with (int ...): NaN -> 0, floats/ratios truncate
-   ;; toward zero ((quot x 1)); non-numbers throw. Only then range-check.
+   ;; toward zero; non-numbers throw. Only then range-check.
    (let [coerce (fn [x]
                   (cond
                     (not (number? x)) (throw (str "subvec index must be a number"))
                     (not= x x) 0
-                    :else (quot x 1)))
+                    :else (long x)))
          s (coerce start)
          e (coerce end)]
      (when (or (< s 0) (< e s) (< (count v) e))

jolt-core/clojure/core/30-macros.clj

@@ -122,8 +122,11 @@
   `(bound-fn* (fn ~@fntail)))
 
 (defmacro defonce [name expr]
+  ;; only def when the var has no root value. In a top-level (do ...) the name is
+  ;; already interned (an unbound cell) by the time this runs, so check bound? —
+  ;; var-get would throw on the unbound cell.
   `(let [v# (resolve (quote ~name))]
-     (if (and v# (some? (var-get v#)))
+     (if (and v# (bound? v#))
        v#
        (def ~name ~expr))))