服务器缓存按期限清理，审计快照默认不再落地

排盘缓存、官方快照、负缓存、网关任务和分盘段过期后会删掉。同一张盘的数字写法合成一把缓存键。失败快照只用短期限。自测留存、异步任务、增长合同、安全缓存和隐私标记；一万个文件的清理慢于 2 秒，命中率提升不到 2.5 倍，都按实测写入记录。

Co-Authored-By: Grok (agent loop)

scripts/research/api_chart_cache_byte_diff.py

@@ -0,0 +1,28 @@
+"""Byte-compare numeric chart-cache spellings. See api_disk_cache_ab.py."""
+from __future__ import annotations
+
+import json
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+
+import api_disk_cache_ab as ab
+
+
+def main() -> dict:
+    parent_error = None
+    try:
+        parent = ab._load_parent()
+    except Exception as exc:
+        parent = None
+        parent_error = exc.__class__.__name__
+    report = ab.run_byte_diff(parent or ab.current)
+    report["parent_import"] = parent_error or "ok"
+    report["parent"] = ab.PARENT
+    return report
+
+
+if __name__ == "__main__":
+    json.dump(main(), sys.stdout, ensure_ascii=False, indent=2)
+    sys.stdout.write("\n")