feat(overlay): add position customization for overlay placement

- Introduce PositionX and PositionY fields in OverlaySettings to allow manual positioning of the overlay.
- Update validation to ensure PositionX and PositionY are not less than -1.
- Modify diskConfig to include new position fields for JSON serialization.
- Implement functionality to save overlay position during drag events in the GUI.
- Enhance overlay placement logic to respect user-defined positions while ensuring proper display behavior.

src/config/store.go

@@ -44,6 +44,8 @@ type diskConfig struct {
 		Monitor      string         `json:"monitor"`
 		FinalTimeout string         `json:"final_timeout"`
 		ClickThrough bool           `json:"click_through"`
+		PositionX    *int           `json:"position_x,omitempty"`
+		PositionY    *int           `json:"position_y,omitempty"`
 	} `json:"overlay"`
 	TranscriptLog struct {
 		Enabled   bool   `json:"enabled"`
@@ -163,6 +165,10 @@ func diskFromConfig(config AppConfig) diskConfig {
 	disk.Overlay.Monitor = config.Overlay.Monitor
 	disk.Overlay.FinalTimeout = config.Overlay.FinalTimeout.String()
 	disk.Overlay.ClickThrough = config.Overlay.ClickThrough
+	positionX := config.Overlay.PositionX
+	positionY := config.Overlay.PositionY
+	disk.Overlay.PositionX = &positionX
+	disk.Overlay.PositionY = &positionY
 	disk.TranscriptLog.Enabled = config.TranscriptLog.Enabled
 	disk.TranscriptLog.Directory = config.TranscriptLog.Directory
 	return disk
@@ -185,6 +191,13 @@ func (disk diskConfig) toConfig() (AppConfig, error) {
 	if err != nil {
 		return AppConfig{}, err
 	}
+	positionX, positionY := -1, -1
+	if disk.Overlay.PositionX != nil {
+		positionX = *disk.Overlay.PositionX
+	}
+	if disk.Overlay.PositionY != nil {
+		positionY = *disk.Overlay.PositionY
+	}
 	return AppConfig{
 		Version: disk.Version,
 		GUI: GUISettings{
@@ -218,6 +231,8 @@ func (disk diskConfig) toConfig() (AppConfig, error) {
 			Monitor:      disk.Overlay.Monitor,
 			FinalTimeout: finalTimeout,
 			ClickThrough: disk.Overlay.ClickThrough,
+			PositionX:    positionX,
+			PositionY:    positionY,
 		},
 		TranscriptLog: TranscriptLogSettings{
 			Enabled:   disk.TranscriptLog.Enabled,