Document design choices and standardize Dockerfile

assets/assets.go

@@ -6,9 +6,21 @@ import (
 	"fyne.io/fyne/v2"
 )
 
+// The application icon is embedded into the binary instead of being loaded from
+// an assets directory at runtime. That keeps the Windows/Linux distribution to a
+// single executable and avoids the common failure mode where the app starts with
+// a generic icon because a sidecar PNG was not copied with the binary.
+//
+// The blank import enables the compiler directive below; no runtime package
+// initialization from embed is required.
+//
 //go:embed pysentry-icon.png
 var iconBytes []byte
 
 func Icon() fyne.Resource {
+	// Fyne accepts resources from memory, so the same embedded PNG can be used
+	// for the window icon and tray icon. The Windows Explorer icon is still added
+	// by the build script through the .ico resource, because Explorer reads PE
+	// resources rather than Fyne runtime state.
 	return fyne.NewStaticResource("pysentry-icon.png", iconBytes)
 }