fix(zhihu): remove noscript tags to prevent duplicate images

Zhihu HTML structure includes noscript fallback images:
<figure><img data-actualsrc=...><noscript><img src=...></noscript></figure>

After fixing lazy-load (replacing src with data-actualsrc), both imgs
have real URLs, causing duplicates. The fix removes noscript tags before
processing img elements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_zhihu_metadata/test_markdown_converter.py

@@ -105,6 +105,30 @@ class TestMarkdownConverterImages:
         assert "https://pic.zhimg.com/fig.jpg" in result
         assert "Image caption" in result
 
+    def test_noscript_images_not_duplicated(self):
+        """Test that images inside noscript tags don't cause duplicates
+
+        Zhihu HTML structure includes noscript fallback images:
+        <figure><img data-actualsrc=...><noscript><img src=...></noscript></figure>
+
+        After fixing lazy-load, both imgs would have real URLs, causing duplicates.
+        The fix removes noscript tags before processing.
+        """
+        html = '''
+        <figure>
+            <img src="data:image/svg+xml;..." data-actualsrc="https://pic.zhimg.com/test.jpg">
+            <noscript>
+                <img src="https://pic.zhimg.com/test.jpg">
+            </noscript>
+        </figure>
+        '''
+        converter = MarkdownConverter()
+        result = converter.convert(html)
+
+        # Should appear exactly once, not twice
+        assert result.count("zhimg.com") == 1
+        assert "https://pic.zhimg.com/test.jpg" in result
+
     def test_empty_src_with_data_actualsrc(self):
         """Test handling of empty src with data-actualsrc"""
         html = '<img src="" data-actualsrc="https://example.com/fallback.jpg">'