Fix edge cases: 864/870 JS full, 747/747 standard, 679/679 Python

- Fix deftype tests: use (list ...) instead of bare (...) for type
  bodies in dict literals. CEK evaluates dict values, so bare lists
  are treated as function calls. Tree-walk was more permissive.
- Fix dotimes macro: use for-each+range instead of named-let+set!
  (named-let + set! has a scope chain issue under CEK env-merge)
- Remaining 6 failures are CEK multi-shot continuation limitations:
  k invoked multiple times, scope/provide across shift boundaries.
  These need frame copying for multi-shot support (future work).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/scripts/sx-browser.js

@@ -14,7 +14,7 @@
   // =========================================================================
 
   var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
-  var SX_VERSION = "2026-03-15T12:48:42Z";
+  var SX_VERSION = "2026-03-15T13:02:48Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }