fix(window): use detected screen size for tiling

pkg/window/messages.go

@@ -58,7 +58,8 @@ type TaskOpenWindow struct {
 	Opts   []WindowOption
 }
 
-// TaskCloseWindow closes a window. Handler persists state BEFORE emitting ActionWindowClosed.
+// TaskCloseWindow closes a window after persisting state.
+// Platform close events emit ActionWindowClosed through the tracked window handler.
 type TaskCloseWindow struct{ Name string }
 
 // TaskSetPosition moves a window.

pkg/window/mock_platform.go

@@ -63,7 +63,10 @@ func (w *MockWindow) Maximise()                            { w.maximised = true;
 func (w *MockWindow) Restore()                             { w.maximised = false; w.minimised = false; w.visible = true }
 func (w *MockWindow) Minimise()                            { w.minimised = true; w.maximised = false; w.visible = false }
 func (w *MockWindow) Focus()                               { w.focused = true }
-func (w *MockWindow) Close()                               { w.closed = true }
+func (w *MockWindow) Close() {
+	w.closed = true
+	w.emit(WindowEvent{Type: "close", Name: w.name})
+}
 func (w *MockWindow) Show()                                { w.visible = true }
 func (w *MockWindow) Hide()                                { w.visible = false }
 func (w *MockWindow) Fullscreen()                          {}
@@ -76,3 +79,15 @@ func (w *MockWindow) OnWindowEvent(handler func(WindowEvent)) {
 func (w *MockWindow) OnFileDrop(handler func(paths []string, targetID string)) {
 	w.fileDropHandlers = append(w.fileDropHandlers, handler)
 }
+
+func (w *MockWindow) emit(e WindowEvent) {
+	for _, h := range w.eventHandlers {
+		h(e)
+	}
+}
+
+func (w *MockWindow) emitFileDrop(paths []string, targetID string) {
+	for _, h := range w.fileDropHandlers {
+		h(paths, targetID)
+	}
+}

pkg/window/mock_test.go

@@ -63,7 +63,10 @@ func (w *mockWindow) Maximise()                            { w.maximised = true;
 func (w *mockWindow) Restore()                             { w.maximised = false; w.minimised = false; w.visible = true }
 func (w *mockWindow) Minimise()                            { w.minimised = true; w.maximised = false; w.visible = false }
 func (w *mockWindow) Focus()                               { w.focused = true }
-func (w *mockWindow) Close()                               { w.closed = true }
+func (w *mockWindow) Close() {
+	w.closed = true
+	w.emit(WindowEvent{Type: "close", Name: w.name})
+}
 func (w *mockWindow) Show()                                { w.visible = true }
 func (w *mockWindow) Hide()                                { w.visible = false }
 func (w *mockWindow) Fullscreen()                          {}

pkg/window/service.go

@@ -274,7 +274,6 @@ func (s *Service) taskCloseWindow(name string) error {
 	s.manager.State().CaptureState(pw)
 	pw.Close()
 	s.manager.Remove(name)
-	_ = s.Core().ACTION(ActionWindowClosed{Name: name})
 	return nil
 }
 
@@ -454,8 +453,8 @@ func (s *Service) taskTileWindows(mode string, names []string) error {
 	if len(names) == 0 {
 		names = s.manager.List()
 	}
-	// Default screen size — callers can query screen_primary for actual values.
-	return s.manager.TileWindows(tm, names, 1920, 1080)
+	screenW, screenH := s.primaryScreenSize()
+	return s.manager.TileWindows(tm, names, screenW, screenH)
 }
 
 var snapPosMap = map[string]SnapPosition{

pkg/window/service_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"forge.lthn.ai/core/go/pkg/core"
+	"forge.lthn.ai/core/gui/pkg/screen"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -22,6 +23,41 @@ func newTestWindowService(t *testing.T) (*Service, *core.Core) {
 	return svc, c
 }
 
+type testScreenPlatform struct {
+	screens []screen.Screen
+}
+
+func (p *testScreenPlatform) GetAll() []screen.Screen { return p.screens }
+
+func (p *testScreenPlatform) GetPrimary() *screen.Screen {
+	for i := range p.screens {
+		if p.screens[i].IsPrimary {
+			return &p.screens[i]
+		}
+	}
+	return nil
+}
+
+func newTestWindowServiceWithScreen(t *testing.T) (*Service, *core.Core) {
+	t.Helper()
+	c, err := core.New(
+		core.WithService(Register(newMockPlatform())),
+		core.WithService(screen.Register(&testScreenPlatform{
+			screens: []screen.Screen{{
+				ID: "primary", Name: "Primary", IsPrimary: true,
+				Size:     screen.Size{Width: 2560, Height: 1440},
+				Bounds:   screen.Rect{X: 0, Y: 0, Width: 2560, Height: 1440},
+				WorkArea: screen.Rect{X: 0, Y: 0, Width: 2560, Height: 1440},
+			}},
+		})),
+		core.WithServiceLock(),
+	)
+	require.NoError(t, err)
+	require.NoError(t, c.ServiceStartup(context.Background(), nil))
+	svc := core.MustServiceFor[*Service](c, "window")
+	return svc, c
+}
+
 func TestRegister_Good(t *testing.T) {
 	svc, _ := newTestWindowService(t)
 	assert.NotNil(t, svc)
@@ -218,6 +254,26 @@ func TestTaskSetBackgroundColour_Good(t *testing.T) {
 	assert.Equal(t, [4]uint8{10, 20, 30, 40}, pw.(*mockWindow).backgroundColor)
 }
 
+func TestTaskTileWindows_UsesPrimaryScreenSize(t *testing.T) {
+	_, c := newTestWindowServiceWithScreen(t)
+	_, _, _ = c.PERFORM(TaskOpenWindow{Opts: []WindowOption{WithName("left")}})
+	_, _, _ = c.PERFORM(TaskOpenWindow{Opts: []WindowOption{WithName("right")}})
+
+	_, handled, err := c.PERFORM(TaskTileWindows{Mode: "left-right", Windows: []string{"left", "right"}})
+	require.NoError(t, err)
+	assert.True(t, handled)
+
+	left, _, _ := c.QUERY(QueryWindowByName{Name: "left"})
+	right, _, _ := c.QUERY(QueryWindowByName{Name: "right"})
+	leftInfo := left.(*WindowInfo)
+	rightInfo := right.(*WindowInfo)
+
+	assert.Equal(t, 1280, leftInfo.Width)
+	assert.Equal(t, 1280, rightInfo.Width)
+	assert.Equal(t, 0, leftInfo.X)
+	assert.Equal(t, 1280, rightInfo.X)
+}
+
 func TestTaskSetOpacity_Good(t *testing.T) {
 	_, c := newTestWindowService(t)
 	_, _, _ = c.PERFORM(TaskOpenWindow{Opts: []WindowOption{WithName("test")}})