Refactor: Centralize template context using unified TemplateData struct

- Introduced models.TemplateData for shared user/context state
- Moved context construction logic into handlers/template_context.go
- Simplified helpers.TemplateContext to accept structured data
- Restored and organized template helper functions
- Updated affected handlers (main.go, draw_handler.go, notifications.go)
- Improved scalability and separation of concerns in template rendering

handlers/notifications.go

@@ -0,0 +1,44 @@
+package handlers
+
+import (
+	"net/http"
+	"text/template"
+
+	"synlotto-website/helpers"
+	"synlotto-website/models"
+	"synlotto-website/storage"
+)
+
+func NotificationsHandler(w http.ResponseWriter, r *http.Request) {
+	session, _ := helpers.GetSession(w, r)
+
+	var user *models.User
+	switch v := session.Values["user_id"].(type) {
+	case int:
+		user = models.GetUserByID(v)
+	case int64:
+		user = models.GetUserByID(int(v))
+	}
+
+	var (
+		isAdmin           bool
+		notificationCount int
+		notifications     []models.Notification
+	)
+
+	if user != nil {
+		isAdmin = user.IsAdmin
+		notificationCount = storage.GetNotificationCount(user.Id)
+		notifications = storage.GetRecentNotifications(user.Id, 15)
+	}
+
+	tmpl := template.Must(template.New("notifications.html").
+		Funcs(helpers.TemplateFuncs()).
+		ParseFiles("templates/notifications.html"))
+
+	context := helpers.TemplateContext(w, r, user, isAdmin, notificationCount, notifications)
+
+	if err := tmpl.Execute(w, context); err != nil {
+		http.Error(w, "Template rendering error", http.StatusInternalServerError)
+	}
+}