fix(test): make restart-path tests independent of the CI runner

GitHub Actions runs jobs under systemd, so INVOCATION_ID is set on the
runner and update.IsSystemd() reports true there but false on a
developer machine. The systemd branch then short-circuited before the
launchd and container branches, failing six restart-path tests in CI
while passing locally.

Clear INVOCATION_ID in both TestMains so branch selection is
deterministic; the systemd tests opt back in explicitly.

Author: prakersh

internal/update/update_testmain_test.go

@@ -11,6 +11,12 @@ import (
 // reaches Restart(). Tests that exercise the launchd branch override the hooks
 // themselves.
 func TestMain(m *testing.M) {
+	// GitHub Actions runs jobs under systemd, so INVOCATION_ID is set on the
+	// runner and IsSystemd() reports true there but not on a developer
+	// machine. Clear it so Restart()'s branch selection is deterministic; the
+	// systemd tests set it explicitly.
+	os.Unsetenv("INVOCATION_ID")
+
 	launchdSupported = func() bool { return false }
 	launchdInstalled = func() bool { return false }
 	launchdLoaded = func() bool { return false }

main_testmain_test.go

@@ -20,6 +20,12 @@ func TestMain(m *testing.M) {
 	os.Unsetenv("OPENCODE_HOME")
 	os.Unsetenv("XDG_DATA_HOME")
 
+	// GitHub Actions runs jobs under systemd, so INVOCATION_ID is set on the
+	// runner and update.IsSystemd() reports true there but not on a developer
+	// machine. Clear it so the restart-path tests see the same world in both
+	// places; the systemd test opts back in with t.Setenv.
+	os.Unsetenv("INVOCATION_ID")
+
 	// Auto-start and daemon-spawn safety net: no test may shell out to
 	// launchctl, touch the developer's real LaunchAgents directory, or start a
 	// real onWatch daemon (which would poll live provider APIs). Tests that