fix(transfer): tolerate one-second mtime drift

app/application/history/retry.py

@@ -18,8 +18,8 @@ from app.runtime.log import logger
 MIN_FAILED_RETRIES = 1
 MAX_FAILED_RETRIES = 10
 FAILED_RETRY_TTL = 24 * 3600
-# 不同存储后端对秒级修改时间的浮点和序列化误差可能达到毫秒；更大的变化仍视为新版本。
-MODIFY_TIME_TOLERANCE = 1e-3
+# 不同存储后端的修改时间精度和序列化可能产生秒级差异；超过 1 秒才视为新版本。
+MODIFY_TIME_TOLERANCE = 1.0
 
 # 缓存值会同时保存文件指纹，使同一路径的新版本获得独立重试预算。
 _failed_retry_counts = TTLCache(

tests/test_transfer_history_gate.py

@@ -82,14 +82,14 @@ def test_evaluate_history_gate_skips_when_success_size_unchanged():
 @pytest.mark.parametrize(
     "current_modify_time, expected",
     [
-        (100.0005, HistoryGateAction.SKIP),
-        (100.01, HistoryGateAction.PASS_SIZE_CHANGED),
+        (101.0, HistoryGateAction.SKIP),
+        (101.01, HistoryGateAction.PASS_SIZE_CHANGED),
     ],
 )
 def test_evaluate_history_gate_uses_tolerance_for_modify_time(
         current_modify_time, expected,
 ):
-    """修改时间仅有毫秒级浮点漂移时应保持原版本，明显变化仍应放行。"""
+    """修改时间变化不超过 1 秒时应保持原版本，超过 1 秒仍应放行。"""
     history = make_history(status=True, size=1024, modify_time=100.0)
 
     action = evaluate_history_gate(