fix(e2e): read setup-token via exec; reclaim /data

Container startup is green; CI failed because panel-owned setup-token (0600)
was unreadable on the host bind mount, and TempDir cleanup hit EACCES on
sqlite/opendkim files. Read the token with compose exec (as guide.md) and
chown /data before removing containers/stage.

Co-Authored-By: Composer <noreply@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

test/e2e/hostname_gate_test.go

@@ -88,7 +88,14 @@ func runEntrypointBackground(t *testing.T, hostnameEnv string) (output string, s
 	}
 	name := "selfpost-e2e-hostname-check"
 	_ = exec.Command("docker", "rm", "-f", name).Run()
-	defer exec.Command("docker", "rm", "-f", name).Run()
+	defer func() {
+		// Make bind-mounted /data deletable by Go's TempDir cleanup: the panel
+		// leaves setup-token/db/opendkim owned by container UIDs (CI failed the
+		// subtest on testing.go TempDir RemoveAll even when start succeeded).
+		_ = exec.Command("docker", "exec", name, "sh", "-c",
+			"chown -R root:root /data && chmod -R a+rwX /data").Run()
+		_ = exec.Command("docker", "rm", "-f", name).Run()
+	}()
 
 	// #region agent log
 	if fi, err := os.Stat(dataDir); err == nil {