feat: 内容数据迁移至数据库，合规审查全链路打通

- 文章 HTML 存储从文件系统迁移至 articles 表，删除 releases 目录
- 合规审查从 DB 读取 HTML，审查结果写回 DB，通过后自动推进至待发布
- 新增 todayCount 筛选按钮，与系统概览统计数据一致
- 全屏预览修复：提升 z-index 超过侧边栏，添加退出全屏/关闭按钮
- 统一 '优化' → '审查' 命名，消除前后端术语不一致
- 调度器创作完成后自动触发审查（生成 → 审查 → 待发布）
- 清理旧备份/调试文件、过期大纲和研究笔记

platform/backend/app/main.py

@@ -11,14 +11,33 @@ from .database import engine, get_db, init_db
 from .models import Base
 from .api import topics, system, articles, publishing, auth, admin, audit, optimizer_logs, cases, task_logs, llm_configs, system_configs, topic_config, calendar, metrics, assets, tasks, platform_config
 from .initial_data import import_initial_data
+from .core.scheduler import scheduler
 
 app = FastAPI(title="宇之然内容创作平台", version="0.1.0")
 logger = logging.getLogger(__name__)
 
-# CORS
+
+@app.on_event("startup")
+def start_scheduler():
+    scheduler.start()
+    logger.info("Background scheduler started")
+
+
+@app.on_event("shutdown")
+def stop_scheduler():
+    scheduler.shutdown()
+    logger.info("Background scheduler shut down")
+
+# CORS - local-only origins
+_local_origins = [
+    "http://localhost:8001",
+    "http://127.0.0.1:8001",
+    "http://localhost:8000",
+    "http://127.0.0.1:8000",
+]
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=["*"],
+    allow_origins=_local_origins,
     allow_credentials=True,
     allow_methods=["*"],
     allow_headers=["*"],