feat(web): integrate ecosystem social preview images

tests/unit_tests/test_social_preview.py

@@ -0,0 +1,28 @@
+import importlib.util
+from pathlib import Path
+import unittest
+
+ROOT = Path(__file__).resolve().parents[2]
+spec = importlib.util.spec_from_file_location('social_preview', ROOT / 'src/langbot/pkg/api/http/controller/social_preview.py')
+assert spec is not None and spec.loader is not None
+module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(module)
+
+
+class SocialPreviewTest(unittest.TestCase):
+    def test_cloud_has_crawler_visible_image(self):
+        html = (ROOT / 'web/index.html').read_text()
+        result = module.cloud_preview_html(html, 'cloud.langbot.app')
+        self.assertIn(module.CLOUD_IMAGE, result)
+        self.assertIn('summary_large_image', result)
+        self.assertEqual(result.count('property="og:image"'), 1)
+        self.assertTrue((ROOT / 'web/public/social/cloud-v3.png').is_file())
+
+    def test_self_hosted_is_unchanged(self):
+        html = '<head><title>LangBot</title></head>'
+        for host in ['localhost:5300', 'example.com', 'cloud.langbot.app.evil.com']:
+            self.assertEqual(module.cloud_preview_html(html, host), html)
+
+
+if __name__ == '__main__':
+    unittest.main()