perf: SQLite WAL + 复合索引 + GZip + scheduler jitter + 构建缓存

backend/app/models/website.py

@@ -1,7 +1,7 @@
 from datetime import datetime, timezone
 from typing import Optional
 
-from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy import Boolean, DateTime, ForeignKey, Index, Integer, String, Text, text
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.database import Base
@@ -66,3 +66,8 @@ class WebsiteSyncLog(Base):
     status: Mapped[str] = mapped_column(String(16), nullable=False)
     message: Mapped[str] = mapped_column(Text, default="")
     created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc), index=True)
+
+    __table_args__ = (
+        Index("ix_sync_website_created", "website_id", text("created_at DESC")),
+        Index("ix_sync_binding_created", "binding_id", text("created_at DESC")),
+    )