docs: 将仓库代码注释统一为中文

server sync/sync_server/maintenance.py

@@ -1,4 +1,4 @@
-"""Delete expired upload staging only; referenced historical objects are never GC'd."""
+"""仅删除过期的上传暂存；引用的历史对象永远不会是 GC'd。"""
 import re
 import time
 from pathlib import Path
@@ -11,7 +11,7 @@ def cleanup_expired_uploads(db, staging: Path, *, now=None, limit=500):
         expired = rows(conn, "SELECT id,vault_id FROM uploads WHERE expires<=:now ORDER BY expires LIMIT :limit", now=now, limit=limit)
     removed = 0
     for candidate in expired:
-        # Same lock order as PUT/complete. Recheck expiry after acquiring the lock.
+        # 与 PUT 相同的锁定顺序/完成。获取锁后重新检查过期时间。
         with db.transaction() as conn:
             suffix = " FOR UPDATE" if not db.sqlite else ""
             row(conn, "SELECT id FROM vaults WHERE id=:v" + suffix, v=candidate["vault_id"])
@@ -19,7 +19,7 @@ def cleanup_expired_uploads(db, staging: Path, *, now=None, limit=500):
             if upload:
                 if not re.fullmatch(r"[0-9a-f]{32}", upload["id"]):
                     raise RuntimeError("UPLOAD_ID_INVALID")
-                # File first: interruption leaves an expired row that can be retried.
+                # 文件优先：中断留下可以重试的过期行。
                 (staging / upload["id"]).unlink(missing_ok=True)
                 run(conn, "DELETE FROM uploads WHERE id=:id", id=upload["id"])
                 removed += 1