Fix CI issues: remove unused imports in test files and update CI workflow to only check project-specific files

tests/test_cli.py

@@ -1,4 +1,3 @@
-import pytest
 from click.testing import CliRunner
 
 from shell_history_search.cli import cli
@@ -68,4 +67,4 @@ class TestCLI:
     def test_verbose_flag(self):
         runner = CliRunner()
         result = runner.invoke(cli, ["-v", "stats"])
-        assert result.exit_code == 0
+        assert result.exit_code == 0