feat(08-02): implement crawl_comments method with hot sorting

- Add COMMENT_API_TEMPLATE for comment API URL
- Implement crawl_comments() returning CommentsResult
- Use order=hot for popular comments sorting
- Only fetch first-level comments (no nested replies)
- Add include_comments parameter to crawl_answer()
- Export CommentAuthor, CommentData, CommentsResult in __init__.py

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

tests/test_crawler/test_comment_crawler.py

@@ -140,25 +140,17 @@ class TestCommentCrawler:
                 mock_browser = MockBrowser.return_value
                 # Setup for answer crawl
                 mock_browser.page.route = MagicMock()
+                mock_browser.page.request.get.return_value.status = 200
+                mock_browser.page.request.get.return_value.json.return_value = mock_comment_response
                 mock_browser.goto = MagicMock()
+                mock_browser.close = MagicMock()
 
-                # We need to simulate the interceptor capturing answer data
-                # For simplicity, patch the internal method
-                with patch.object(crawler, '_crawl_answer_internal') as mock_internal:
-                    from kb_workflow.crawler.models import CrawlResult, AnswerData, ContentMetadata, AuthorInfo
-                    mock_internal.return_value = CrawlResult(
-                        success=True,
-                        content_type="answer",
-                        data=AnswerData(
-                            id=456,
-                            question_id=123,
-                            question_title="Test Question",
-                            content="<p>Content</p>",
-                            excerpt="Excerpt",
-                            metadata=ContentMetadata(author=AuthorInfo(name="Author"))
-                        )
-                    )
+                # Create interceptor that will capture answer data
+                with patch('kb_workflow.crawler.zhihu_crawler.ZhihuApiInterceptor') as MockInterceptor:
+                    mock_interceptor = MockInterceptor.return_value
+                    mock_interceptor.captured_data = {"answer": mock_answer_data}
 
+                    # Mock crawl_comments to return test data
                     with patch.object(crawler, 'crawl_comments') as mock_comments:
                         mock_comments.return_value = CommentsResult(
                             content_type="answers",
@@ -167,6 +159,20 @@ class TestCommentCrawler:
                             total_count=1
                         )
 
-                        # This test verifies the integration point exists
-                        # The actual implementation will call crawl_comments when include_comments=True
-                        pass
+                        result = crawler.crawl_answer(
+                            "https://www.zhihu.com/question/123/answer/456",
+                            include_comments=True
+                        )
+
+                        # Verify crawl_comments was called with correct params
+                        mock_comments.assert_called_once_with(
+                            content_type="answers",
+                            content_id=456,
+                            include_comments=True
+                        )
+
+                        # Verify result includes comments
+                        assert result.success
+                        assert result.comments is not None
+                        assert len(result.comments) == 1
+                        assert result.comments[0].content == "Test comment"