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>

compose.enterprise.yaml

@@ -6,7 +6,7 @@ services:
       dockerfile: Dockerfile.enterprise
       args:
         SITEFORGE_GIT_SHA: ${SITEFORGE_GIT_SHA:-unknown}
-    image: siteforge/web:8.21.3-dev.1
+    image: siteforge/web:8.31.0-dev.1
     init: true
     restart: unless-stopped
     ports:
@@ -48,7 +48,7 @@ services:
       retries: 3
       start_period: 30s
   worker:
-    image: siteforge/web:8.21.3-dev.1
+    image: siteforge/web:8.31.0-dev.1
     command: ['python','-m','app.worker']
     init: true
     restart: unless-stopped