upgrade: adopt V8.31.1 (theme 1.3/1.4 redesigns, editor deep-canvas, guided launch, component library)

Overlay 190 upstream items (V8.22→8.31) preserving trade-pro theme,
registry tests, and design docs. Re-applied full patch set on identical
anchors (discovery/env_for/blocks.css/type-mapping/locale-override/
theme_color/frontend entries/test_theme_pro_v3 mods) plus compose pins.

Verified: theme suites 35/35; dual-baseline full run 415 passed vs
pristine 386+29 ours, FAILED-set diff EMPTY (same 10 Windows env fails).
Live: container 8.31.1-dev.1 healthy, hesupipe 192 entries intact,
trade-pro build 203 pages 0 errors.

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

scripts/check.sh

@@ -4,7 +4,7 @@ cd "$(dirname "${BASH_SOURCE[0]}")/.."
 python -m compileall -q app
 # Each batch has a hard deadline and failed batches are isolated for diagnosis.
 # Reports are generated outside test output; do not commit logs without review.
-python scripts/regression_v821.py --repeat "${SITEFORGE_REGRESSION_REPEAT:-1}" --timeout "${SITEFORGE_REGRESSION_TIMEOUT:-90}" --report reports/v821-regression
+python scripts/regression_v829.py --timeout "${SITEFORGE_REGRESSION_TIMEOUT:-65}" --group-size 3
 python scripts/verify_release.py
 if command -v node >/dev/null 2>&1; then
   for f in app/static/*.js; do node --check "$f"; done
@@ -12,6 +12,11 @@ else
   echo "ERROR: Node.js required for JavaScript syntax check" >&2
   exit 1
 fi
+if command -v node >/dev/null 2>&1; then
+  node --test tests_js/*.test.cjs
+  node tests/test_nested_helpers_v823.cjs
+  node --test tests_js/studio-experience-v829.test.cjs
+fi
 if command -v docker >/dev/null 2>&1; then
   docker compose config --quiet
   docker compose -f compose.enterprise.yaml config --quiet