kernel: map/filter/reduce + with-env applicative constructor + 10 tests [shapes-reflective]

Added kernel-make-primitive-applicative-with-env in eval.sx — IMPL
receives (args dyn-env), needed by combinators that re-enter the
evaluator. map/filter/reduce in runtime.sx use it to call user-supplied
combiners on each element with the caller's dynamic env preserved.
Sketched the env-blind vs env-aware applicative split as a new entry
in the proposed combiner.sx reflective API. 289 tests total.

lib/kernel/tests/standard.sx

@@ -363,4 +363,36 @@
 (ks-test "<=? violation"          (ks-eval "(<=? 1 2 1)") false)
 (ks-test ">=? descending equals" (ks-eval "(>=? 3 3 2 1)") true)
 
+;; ── list combinators ────────────────────────────────────────────
+(ks-test "map: square"
+  (ks-eval "(map ($lambda (x) (* x x)) (list 1 2 3 4))")
+  (list 1 4 9 16))
+(ks-test "map: empty list"
+  (ks-eval "(map ($lambda (x) x) (list))") (list))
+(ks-test "map: identity preserves"
+  (ks-eval "(map ($lambda (x) x) (list 1 2 3))") (list 1 2 3))
+(ks-test "map: with closure over outer"
+  (let ((env (kernel-standard-env)))
+    (ks-eval-in "($define! k 10)" env)
+    (ks-eval-in "(map ($lambda (x) (+ x k)) (list 1 2 3))" env))
+  (list 11 12 13))
+
+(ks-test "filter: positives"
+  (ks-eval "(filter ($lambda (x) (< 0 x)) (list -2 -1 0 1 2))")
+  (list 1 2))
+(ks-test "filter: empty result"
+  (ks-eval "(filter ($lambda (x) #f) (list 1 2 3))") (list))
+(ks-test "filter: all match"
+  (ks-eval "(filter ($lambda (x) #t) (list 1 2 3))") (list 1 2 3))
+
+(ks-test "reduce: sum"
+  (ks-eval "(reduce ($lambda (a b) (+ a b)) 0 (list 1 2 3 4 5))") 15)
+(ks-test "reduce: product"
+  (ks-eval "(reduce ($lambda (a b) (* a b)) 1 (list 1 2 3 4))") 24)
+(ks-test "reduce: empty returns init"
+  (ks-eval "(reduce ($lambda (a b) (+ a b)) 42 (list))") 42)
+(ks-test "reduce: build list"
+  (ks-eval "(reduce ($lambda (acc x) (cons x acc)) () (list 1 2 3))")
+  (list 3 2 1))
+
 (define ks-tests-run! (fn () {:total (+ ks-test-pass ks-test-fail) :passed ks-test-pass :failed ks-test-fail :fails ks-test-fails}))