Fix Android startup defaults and window sizing

main.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"slices"
 	"strings"
 	"time"
@@ -413,6 +414,17 @@ func resolveFlagOrEnv(flagValue, envName, fallback string) string {
 	return fallback
 }
 
+func defaultModeForRuntime(goos string) string {
+	if strings.EqualFold(strings.TrimSpace(goos), "android") {
+		return "phone"
+	}
+	return "desktop"
+}
+
+func shouldUsePreviewWindowSize(mode, goos string) bool {
+	return !strings.EqualFold(strings.TrimSpace(goos), "android")
+}
+
 func (u *ui) selectedAttachmentItems() []attachmentItem {
 	item, ok := u.selectedEntry()
 	if !ok || len(item.Attachments) == 0 {
@@ -2903,7 +2915,7 @@ func main() {
 	stateDir := flag.String("state-dir", "", "directory for KeePassGO state such as recent-vault history and default save targets")
 	flag.Parse()
 
-	resolvedMode := resolveFlagOrEnv(*mode, "KEEPASSGO_MODE", "desktop")
+	resolvedMode := resolveFlagOrEnv(*mode, "KEEPASSGO_MODE", defaultModeForRuntime(runtime.GOOS))
 	resolvedStateDir := resolveFlagOrEnv(*stateDir, "KEEPASSGO_STATE_DIR", "")
 
 	width := unit.Dp(1180)
@@ -2916,14 +2928,17 @@ func main() {
 
 	go func() {
 		w := new(app.Window)
-		w.Option(
-			app.Title(productName),
-			app.Size(width, height),
-		)
+		options := []app.Option{app.Title(productName)}
+		if shouldUsePreviewWindowSize(resolvedMode, runtime.GOOS) {
+			options = append(options, app.Size(width, height))
+		}
+		w.Option(options...)
 		if err := run(w, strings.ToLower(resolvedMode), defaultStatePaths(resolvedStateDir)); err != nil {
 			panic(err)
 		}
-		os.Exit(0)
+		if !strings.EqualFold(runtime.GOOS, "android") {
+			os.Exit(0)
+		}
 	}()
 	app.Main()
 }

main_test.go

@@ -2348,6 +2348,31 @@ func TestResolveFlagOrEnvPrefersFlagThenEnvThenFallback(t *testing.T) {
 	}
 }
 
+func TestDefaultModeForRuntimeUsesPhoneOnAndroid(t *testing.T) {
+	t.Parallel()
+
+	if got := defaultModeForRuntime("android"); got != "phone" {
+		t.Fatalf("defaultModeForRuntime(android) = %q, want %q", got, "phone")
+	}
+	if got := defaultModeForRuntime("linux"); got != "desktop" {
+		t.Fatalf("defaultModeForRuntime(linux) = %q, want %q", got, "desktop")
+	}
+}
+
+func TestShouldUsePreviewWindowSizeSkipsAndroid(t *testing.T) {
+	t.Parallel()
+
+	if got := shouldUsePreviewWindowSize("desktop", "android"); got {
+		t.Fatal("shouldUsePreviewWindowSize(desktop, android) = true, want false")
+	}
+	if got := shouldUsePreviewWindowSize("phone", "android"); got {
+		t.Fatal("shouldUsePreviewWindowSize(phone, android) = true, want false")
+	}
+	if got := shouldUsePreviewWindowSize("desktop", "linux"); !got {
+		t.Fatal("shouldUsePreviewWindowSize(desktop, linux) = false, want true")
+	}
+}
+
 func TestEnterOnLocalLifecycleScreenDefaultsToOpenVault(t *testing.T) {
 	t.Parallel()