Add main settings view and theme management functionality

Introduce a new `MainSettings` view for managing application settings, including language and theme selection. Implement theme management methods in the `setting` package to handle theme initialization, retrieval, and updates.

internal/application/setting/theme.go

@@ -0,0 +1,110 @@
+package setting
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/lang"
+	"fyne.io/fyne/v2/theme"
+	"image/color"
+)
+
+func (s *setting) GetTheme() ThemeInfoContract {
+	name := s.fyneApp.Preferences().String("theme")
+	if name != "" {
+		if _, ok := s.GetThemes()[name]; ok {
+			return s.GetThemes()[name]
+		}
+	}
+
+	return s.GetThemes()["default"]
+}
+
+func (s *setting) SetTheme(themeInfo ThemeInfoContract) {
+	s.fyneApp.Preferences().SetString("theme", themeInfo.GetName())
+
+	if themeInfo.GetName() == "default" {
+		s.fyneApp.Settings().SetTheme(theme.DefaultTheme())
+		return
+	}
+	s.fyneApp.Settings().SetTheme(&forcedVariant{theme: theme.DefaultTheme(), variant: themeInfo.GetVariant()})
+}
+
+func (s *setting) ThemeInit() {
+	themeInfo := s.GetTheme()
+	if themeInfo.GetName() == "default" {
+		s.fyneApp.Settings().SetTheme(theme.DefaultTheme())
+		return
+	}
+	s.fyneApp.Settings().SetTheme(&forcedVariant{theme: theme.DefaultTheme(), variant: themeInfo.GetVariant()})
+}
+
+func (s *setting) GetThemes() map[string]ThemeInfoContract {
+	themesNameDefault := &themeInfo{
+		name:  "default",
+		title: lang.L("themesNameDefault"),
+	}
+
+	themesNameLight := &themeInfo{
+		name:    "light",
+		title:   lang.L("themesNameLight"),
+		variant: theme.VariantLight,
+	}
+
+	themesNameDark := &themeInfo{
+		name:    "dark",
+		title:   lang.L("themesNameDark"),
+		variant: theme.VariantDark,
+	}
+
+	list := map[string]ThemeInfoContract{
+		"default": themesNameDefault,
+		"light":   themesNameLight,
+		"dark":    themesNameDark,
+	}
+
+	return list
+}
+
+type ThemeInfoContract interface {
+	GetName() string
+	GetTitle() string
+	GetVariant() fyne.ThemeVariant
+}
+
+type themeInfo struct {
+	name    string
+	title   string
+	variant fyne.ThemeVariant
+}
+
+func (inf *themeInfo) GetName() string {
+	return inf.name
+}
+
+func (inf *themeInfo) GetTitle() string {
+	return inf.title
+}
+
+func (inf *themeInfo) GetVariant() fyne.ThemeVariant {
+	return inf.variant
+}
+
+type forcedVariant struct {
+	theme   fyne.Theme
+	variant fyne.ThemeVariant
+}
+
+func (f *forcedVariant) Color(name fyne.ThemeColorName, _ fyne.ThemeVariant) color.Color {
+	return f.theme.Color(name, f.variant)
+}
+
+func (f *forcedVariant) Font(style fyne.TextStyle) fyne.Resource {
+	return theme.DefaultTheme().Font(style)
+}
+
+func (f *forcedVariant) Icon(name fyne.ThemeIconName) fyne.Resource {
+	return theme.DefaultTheme().Icon(name)
+}
+
+func (f *forcedVariant) Size(name fyne.ThemeSizeName) float32 {
+	return theme.DefaultTheme().Size(name)
+}