fix: pipeline content tracking + topic article preview

db_helper.py: save_article now calculates and persists word_count
generator.py: run_creator_blocking sets word_count for HTML-imported articles
writer.py: fix title regex stripping content-leading numbers (35岁后→岁后)
trends.py: fix Baidu hot_score str/int type comparison crash
database.py: add missing content_tasks.org_id ALTER TABLE migration
schemas.py + topics.py: topic list API returns article_count + articles[] previews
topics.html: table view and card view show article badges with word counts, clickable to open preview

Ultraworked with Sisyphus

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

platform/backend/app/schemas.py

@@ -138,6 +138,8 @@ class TopicResponse(TopicBase):
     compliance_score: Optional[int] = None
     platform_urls: Dict[str, str] = {}
     cases: List[Any] = []
+    article_count: int = 0
+    articles: List[Dict[str, Any]] = []
 
     model_config = ConfigDict(from_attributes=True)