feat: trade-pro skeleton theme package (Phase 2)

Fifth built-in theme: English-first international B2B skeleton registered
via manifest discovery, builds real sites end-to-end. pro.html derives
from industrial with lang=en, href-set value-comparison English fallback
nav (header + footer), sf-tp-* button classes and hard-coded #0b3d91
theme-color until the map entry lands. pages/ ships all 14 kinds; macro
library is an English passthrough copy pending the Phase 3 cms port.

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

tests/test_theme_registry.py

@@ -2,6 +2,7 @@
 import json
 from pathlib import Path
 from app import core, theme_pro, theme_store
+from test_factory_v2 import factory, site  # noqa: F401 -- fixture + helper reused by trade-pro tests
 
 ROOT = Path(core.__file__).resolve().parent.parent
 
@@ -92,6 +93,26 @@ def test_env_for_degraded_branch_not_cached_and_single_path(tmp_path, monkeypatc
     finally:
         core.THEMES = core.discover_themes()
 
+def test_trade_pro_registered_and_compatible():
+    assert 'trade-pro' in core.THEMES
+    result = theme_store.compatibility('trade-pro')
+    assert result['valid'], result['errors']
+    assert not result['errors']
+
+def test_trade_pro_builds_real_site(factory):
+    sid = site(factory)
+    assert factory.post(f'/api/factory/sites/{sid}/bootstrap').status_code == 200
+    selected = factory.put(f'/api/factory/sites/{sid}/theme', json={'theme': 'trade-pro', 'version': '1.0.0'})
+    assert selected.status_code == 200, selected.text
+    result = factory.post(f'/api/sites/{sid}/builds', json={})
+    assert result.status_code == 200, result.text
+    bid = result.json()['version']
+    home = factory.get(f'/preview/{sid}/{bid}/')
+    assert home.status_code == 200, home.text[:400]
+    assert 'lang="en"' in home.text
+    assert '>首页<' not in home.text
+    assert '<meta name="theme-color" content="#0b3d91"' in home.text
+
 def test_theme_blocks_css_overrides_platform(tmp_path):
     from app import builder
     dist = tmp_path / 'assets'; dist.mkdir()