test: stop Test_CmdKeys from leaking re-initialized settings

Running the keys command in-process re-initializes settings, and since
cli v3.10 a usage error also prints help (which re-initializes them too).
That repointed the global RepoRootPath to a default under the data dir,
tripping the SyncDirs guard in every later integration test. Set
HideHelp so a usage error no longer prints help during the test.

Assisted-by: Claude:Opus-4.8

tests/integration/cmd_keys_test.go

@@ -38,7 +38,8 @@ func Test_CmdKeys(t *testing.T) {
 			t.Run(tt.name, func(t *testing.T) {
 				// FIXME: this test is not quite right. Each "command run" always re-initializes settings
 				keysCmd := cmd.NewKeysCommand()
-				keysCmd.Before = nil // don't re-initialize logger during the test
+				keysCmd.Before = nil    // don't re-initialize logger during the test
+				keysCmd.HideHelp = true // skip help on usage error, which would re-initialize settings (cli v3.10)
 
 				var stdout, stderr bytes.Buffer
 				app := &cli.Command{