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.

main.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	_ "embed"
 	"fyne.io/fyne/v2"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/convertor"
 	error2 "git.kor-elf.net/kor-elf/gui-for-ffmpeg/error"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/handler"
+	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/resources"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/kernel"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/localizer"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/menu"
@@ -16,12 +18,11 @@ var application kernel.AppContract
 var ffPathUtilities *kernel.FFPathUtilities
 
 func init() {
-	iconResource, _ := fyne.LoadResourceFromPath("icon.png")
 	appMetadata := &fyne.AppMetadata{
 		ID:      "net.kor-elf.projects.gui-for-ffmpeg",
 		Name:    "GUI for FFmpeg",
 		Version: "0.9.0",
-		Icon:    iconResource,
+		Icon:    resources.IconAppLogoResource(),
 	}
 
 	ffPathUtilities = &kernel.FFPathUtilities{FFmpeg: "", FFprobe: "", FFplay: ""}