feat: Wave 2 - API org isolation + factory.html + insights.html

- Add org_id auto-population to articles.py, publishing.py, metrics.py
- Add org_id filtering to search_rankings.py geo endpoints
- Add org_id to calendar.py create/update/delete endpoints
- Add org_id to tasks.py create endpoints
- Create factory.html content pipeline page (3-tab: 待创作/进行中/待审查)
- Create insights.html analytics page (4-tab: 概览/搜索排名/GEO/平台对比)

platform/backend/app/api/articles.py

@@ -160,7 +160,8 @@ def update_article_content(
     if not article:
         article = Article(
             id=article_id, topic_id=topic_id, platform=platform,
-            file_path=f"db:{article_id}", status="draft"
+            file_path=f"db:{article_id}", status="draft",
+            org_id=topic.org_id
         )
         db.add(article)
     article.html_content = html_content