Keep a later config flag when extra words are present.

A non-flag word no longer stops parsing, and a missing home directory refuses to create or rewrite a config instead of writing an empty log path.

Co-authored-by: Cursor <cursoragent@cursor.com>

station/home_test.go

@@ -0,0 +1,52 @@
+package station
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestMissingHomeDoesNotCreateConfig(t *testing.T) {
+	orig := userHomeDir
+	t.Cleanup(func() { userHomeDir = orig })
+	userHomeDir = func() (string, error) {
+		return "", errors.New("no home")
+	}
+
+	path := filepath.Join(t.TempDir(), "lab.json")
+	_, err := New(Options{ConfigPath: path})
+	if err == nil || !strings.HasPrefix(err.Error(), "config path:") {
+		t.Fatalf("New() error = %v, want a config path failure", err)
+	}
+	if _, statErr := os.Stat(path); !errors.Is(statErr, fs.ErrNotExist) {
+		t.Fatalf("stat = %v, want the file absent", statErr)
+	}
+}
+
+func TestMissingHomeDoesNotRewriteConfig(t *testing.T) {
+	orig := userHomeDir
+	t.Cleanup(func() { userHomeDir = orig })
+	userHomeDir = func() (string, error) {
+		return "", errors.New("no home")
+	}
+
+	path := filepath.Join(t.TempDir(), "lab.json")
+	original := []byte("{\"host\":\"127.0.0.1\",\"port\":5308,\"callsign\":\"DL1ABC\",\"authKey\":\"key\",\"talkGroup\":20}\n")
+	if err := os.WriteFile(path, original, 0o640); err != nil {
+		t.Fatal(err)
+	}
+	_, err := New(Options{ConfigPath: path})
+	if err == nil || !strings.HasPrefix(err.Error(), "config path:") {
+		t.Fatalf("New() error = %v, want a config path failure", err)
+	}
+	got, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != string(original) {
+		t.Fatalf("file = %q, want %q", got, original)
+	}
+}