Separate eval from render: render-active? gate in eval-list

eval-list only dispatches to the render adapter when render-active? is true.
render-to-html and aser set render-active! on entry. Pure evaluate() calls
no longer stringify component results through the render adapter.

Fixes component children parity: (defcomp ~wrap (&key &rest children) children)
now returns [1,2,3] in eval mode, renders to "123" only in render mode.

Parity: 112/116 pass (remaining 4 are hand-written evaluator.py bugs).

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

shared/sx/ref/platform_py.py

@@ -524,6 +524,19 @@ def is_render_expr(expr):
 # Render dispatch -- set by adapter
 _render_expr_fn = None
 
+# Render mode flag -- set by render-to-html/aser, checked by eval-list
+# When false, render expressions (HTML tags, components) fall through to eval-call
+_render_mode = False
+
+
+def render_active_p():
+    return _render_mode
+
+
+def set_render_active_b(val):
+    global _render_mode
+    _render_mode = bool(val)
+
 
 def render_expr(expr, env):
     if _render_expr_fn:
@@ -1342,9 +1355,14 @@ def public_api_py(has_html: bool, has_sx: bool, has_deps: bool = False) -> str:
         '',
         'def render(expr, env=None):',
         '    """Render expr to HTML string."""',
+        '    global _render_mode',
         '    if env is None:',
         '        env = {}',
-        '    return render_to_html(expr, env)',
+        '    try:',
+        '        _render_mode = True',
+        '        return render_to_html(expr, env)',
+        '    finally:',
+        '        _render_mode = False',
         '',
         '',
         'def make_env(**kwargs):',