feat(tutorial): implement comprehensive tutorial system with step guidance

- Added tutorial controller to manage tutorial state and progress.
- Introduced HelpButton component for contextual help throughout the application.
- Created various tutorial steps for onboarding and feature guidance.
- Integrated tutorial prompts in multiple components (ChildrenListView, LoginButton, ScheduleModal, etc.) to enhance user experience.
- Implemented logic to show tutorials based on user actions and state.
- Added functionality to dismiss and skip tutorial sessions.
- Established a mechanism to hydrate tutorial state from user profile.

frontend/src/App.vue

@@ -1,10 +1,14 @@
 <template>
   <BackendEventsListener />
   <router-view />
+  <TutorialOverlay />
+  <TutorialChildModeOffer />
 </template>
 
 <script setup lang="ts">
 import BackendEventsListener from '@/components/BackendEventsListener.vue'
+import TutorialOverlay from '@/tutorial/TutorialOverlay.vue'
+import TutorialChildModeOffer from '@/tutorial/TutorialChildModeOffer.vue'
 import { checkAuth } from '@/stores/auth'
 
 checkAuth()