Embed application icon as a resource and refactor icon usage

Replaced the external `icon.png` file with an embedded resource using Go's embed functionality. Updated all references to use the new resource, eliminating the need for the standalone icon file.

internal/resources/icon.go

@@ -0,0 +1,13 @@
+package resources
+
+import (
+	_ "embed"
+	"fyne.io/fyne/v2"
+)
+
+//go:embed icons/logo.png
+var iconAppLogo []byte
+
+func IconAppLogoResource() *fyne.StaticResource {
+	return fyne.NewStaticResource("icon.png", iconAppLogo)
+}