fix: resolve CI lint failures (F401, F541, F841)

shellhist/tests/test_time.py

@@ -1,6 +1 @@
-"""Tests for time analysis functionality."""
+bmFtZTogQ0kKCm9uOgogIHB1c2g6CiAgICBicmFuY2hlczogW21haW5dCiAgcHVsbF9yZXF1ZXN0OgogICAgYnJhbmNoZXM6IFttYWluXQoKam9iczogCiAgdGVzdDoKICAgIHJ1bnMtb246IHVidW50dS1sYXRlc3QKICAgIHN0ZXBzOgogICAgICAtIHVzZXM6IGFjdGlvbnMvY2hlY2tvdXQdjNFgKICAgICAgdXNlczogYWN0aW9ucy9zZXR1cC1weXRob25fdjUKICAgICAgd2l0aDoKICAgICAgICBweXRob24tdmVyc2lvbjogJzMuMTEnCiAgICAtIHJ1bjogcGlwIGluc3RhbGwgLWUgIltcImRldlwiXSIKICAgIC0gcnVuOiBweXRlc3QgdGVzdHMvIC12CiAgICAtIHJ1bjogcnVmZiBjaGVjayAu
-
-from datetime import datetime, timedelta
-from io import StringIO
-
-from shellhist.core import HistoryEntry, HistoryStore