spec: sequence protocol Spec step — seq-to-list + ho polymorphic dispatch

- seq-to-list: coerce list/vector/string/nil to list
- ho-setup-dispatch: apply seq-to-list to all collection args so map/filter/
  reduce/for-each/some/every? work over vectors and strings natively
- sequence->list, sequence->vector, sequence-length, sequence-ref,
  sequence-append: full polymorphic sequence helpers
- in-range: list-returning range generator (eager, works with all HO forms)
- Restore 3 accidentally-deleted make-cek-state/make-cek-value/make-cek-suspended
- Fix 8 shorthand define forms (transpiler requires long form)
- Add vector->list/list->vector to transpiler js-renames + platform aliases
- JS: 2137 passing (+28 vs HEAD baseline)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hosts/javascript/platform.py

@@ -1657,6 +1657,8 @@ PLATFORM_JS_POST = '''
   var mod = PRIMITIVES["mod"];
   var indexOf_ = PRIMITIVES["index-of"];
   var hasKey = PRIMITIVES["has-key?"];
+  var vectorToList = PRIMITIVES["vector->list"];
+  var listToVector = PRIMITIVES["list->vector"];
   function zip(a, b) { var r = []; for (var i = 0; i < Math.min(a.length, b.length); i++) r.push([a[i], b[i]]); return r; }
   function append_b(arr, x) { arr.push(x); return arr; }
   var apply = function(f, args) {