feat: add German and English language switcher

internal/config/config.go

@@ -11,6 +11,7 @@ type Config struct {
 	CheckAUR                bool     `json:"check_aur"`
 	ReminderIntervalHours   int      `json:"reminder_interval_hours"`
 	Terminal                string   `json:"terminal"`
+	Language                string   `json:"language"`
 	AutoRefreshMinutes      int      `json:"auto_refresh_minutes"`
 	ShowIgnored             bool     `json:"show_ignored"`
 	NotificationsEnabled    bool     `json:"notifications_enabled"`
@@ -24,6 +25,7 @@ func Default() Config {
 		CheckAUR:                true,
 		ReminderIntervalHours:   168,
 		Terminal:                "auto",
+		Language:                "de",
 		AutoRefreshMinutes:      30,
 		ShowIgnored:             false,
 		NotificationsEnabled:    true,
@@ -88,6 +90,9 @@ func normalize(cfg Config) Config {
 	if cfg.Terminal == "" {
 		cfg.Terminal = Default().Terminal
 	}
+	if cfg.Language != "de" && cfg.Language != "en" {
+		cfg.Language = Default().Language
+	}
 	if cfg.AutoRefreshMinutes < 0 {
 		cfg.AutoRefreshMinutes = Default().AutoRefreshMinutes
 	}