test(config): remove Windows startup timing assumptions

Cold PowerShell startup under concurrent Windows CI can consume most of the provider timeout, so an unsynchronized PID file may never be written and a fixed four-second bound can fail despite correct process-tree cleanup. Treat an absent PID as a helper that never reached startup, retain strict liveness checks for synchronized children, and bound completion by the child's natural lifetime instead.

internal/config/command_test.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -87,7 +88,7 @@ func TestLoadProviderCommandTimeout(t *testing.T) {
 	if elapsed > maxElapsed {
 		t.Fatalf("timeout returned after %s, want roughly 5s", elapsed)
 	}
-	assertProcessTerminated(t, pidFile)
+	assertProcessTerminatedIfStarted(t, pidFile)
 }
 
 // TestLoadProviderCommandTerminatesBackgroundChild covers a command that
@@ -97,9 +98,10 @@ func TestLoadProviderCommandTimeout(t *testing.T) {
 // leftover child instead of just returning and leaking it.
 func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 	pidFile := filepath.Join(t.TempDir(), "bg.pid")
+	childLifetime := 10 * time.Second
 	command := writeCommand(t, commandScript{
 		Stdout:                 `{"name":"cmd","provider":"openai","apiKey":"sk-command","model":"gpt-command"}`,
-		BackgroundSleepSeconds: 10,
+		BackgroundSleepSeconds: int(childLifetime / time.Second),
 		BackgroundPidFile:      pidFile,
 	})
 
@@ -112,8 +114,8 @@ func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 	if !strings.Contains(err.Error(), "timed out after 5s") {
 		t.Fatalf("error = %q, want timeout", err.Error())
 	}
-	if elapsed > 4*time.Second {
-		t.Fatalf("returned after %s, want well under the 5s provider-command timeout since WaitDelay (1s) should trigger termination", elapsed)
+	if elapsed >= childLifetime {
+		t.Fatalf("returned after %s, want before the background child finishes naturally after %s", elapsed, childLifetime)
 	}
 	assertProcessTerminated(t, pidFile)
 }
@@ -126,10 +128,11 @@ func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 // be terminated on that path.
 func TestLoadProviderCommandTerminatesBackgroundChildOnFailure(t *testing.T) {
 	pidFile := filepath.Join(t.TempDir(), "bg-fail.pid")
+	childLifetime := 10 * time.Second
 	command := writeCommand(t, commandScript{
 		Stderr:                 "boom",
 		ExitCode:               7,
-		BackgroundSleepSeconds: 10,
+		BackgroundSleepSeconds: int(childLifetime / time.Second),
 		BackgroundPidFile:      pidFile,
 	})
 
@@ -142,8 +145,21 @@ func TestLoadProviderCommandTerminatesBackgroundChildOnFailure(t *testing.T) {
 	if !strings.Contains(err.Error(), "exit status") {
 		t.Fatalf("error = %q, want exit status failure", err.Error())
 	}
-	if elapsed > 4*time.Second {
-		t.Fatalf("returned after %s, want well under the 5s provider-command timeout since WaitDelay (1s) should trigger termination", elapsed)
+	if elapsed >= childLifetime {
+		t.Fatalf("returned after %s, want before the background child finishes naturally after %s", elapsed, childLifetime)
+	}
+	assertProcessTerminated(t, pidFile)
+}
+
+func assertProcessTerminatedIfStarted(t *testing.T, pidFile string) {
+	t.Helper()
+
+	// The basic timeout fixture is intentionally unsynchronized. On a loaded
+	// Windows runner, the cold PowerShell child can be terminated before it
+	// records its PID; the synchronized background-child tests below retain
+	// the strict PID and liveness checks.
+	if _, err := os.Stat(pidFile); errors.Is(err, os.ErrNotExist) {
+		return
 	}
 	assertProcessTerminated(t, pidFile)
 }