upgrade: adopt V8.32.0-dev.1 (theme preview iframe fix, editor simple mode)

Overlay 46 upstream items; full patch set re-applied (all patched files
reset by overlay regardless of upstream change status — lesson recorded).
Verified: theme suites 35/35; dual-baseline 418 passed vs pristine
389+29 ours, FAILED-set diff EMPTY (same 10 Windows env fails).
Live: container 8.32.0-dev.1 healthy, hesupipe 192 entries intact,
trade-pro build 203 pages 0 errors.

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

tests/test_theme_pro_v3.py

@@ -31,7 +31,7 @@ def test_four_complete_theme_families_have_distinct_markup(factory):
         import re as _re
         m=_re.search(r'class="((?:pro-home-hero|sf-tp-hero)[^"]*)"',html)
         return m.group(1) if m else html[:40]
-    assert len(set(_hero_sig(s) for s in main))==5  # 5 themes, 5 distinct hero signatures (was 4 before trade-pro)
+    assert len(set(_hero_sig(s) for s in main))==5
 
 
 def test_theme_build_derived_category_brand_search_and_seo(factory):