feat: enhance child edit and view components with improved form handling and validation

- Added `requireDirty` prop to `EntityEditForm` for dirty state management.
- Updated `ChildEditView` to handle initial data loading and image selection more robustly.
- Refactored `ChildView` to remove unused reward dialog logic and prevent API calls in child mode.
- Improved type definitions for form fields and initial data in `ChildEditView`.
- Enhanced error handling in form submissions across components.
- Implemented cross-tab logout synchronization on password reset in the auth store.
- Added tests for login and entity edit form functionalities to ensure proper behavior.
- Introduced global fetch interceptor for handling unauthorized responses.
- Documented password reset flow and its implications on session management.

frontend/vue-app/src/stores/__tests__/auth.childmode.spec.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { isParentAuthenticated, loginUser } from '../auth'
+import { isParentAuthenticated, isUserLoggedIn, loginUser, initAuthSync } from '../auth'
 import { nextTick } from 'vue'
 
 // Helper to mock localStorage
@@ -30,4 +30,20 @@ describe('auth store - child mode on login', () => {
     await nextTick() // flush Vue watcher
     expect(isParentAuthenticated.value).toBe(false)
   })
+
+  it('logs out on cross-tab storage logout event', async () => {
+    initAuthSync()
+    isUserLoggedIn.value = true
+    isParentAuthenticated.value = true
+
+    const logoutEvent = new StorageEvent('storage', {
+      key: 'authSyncEvent',
+      newValue: JSON.stringify({ type: 'logout', at: Date.now() }),
+    })
+    window.dispatchEvent(logoutEvent)
+
+    await nextTick()
+    expect(isUserLoggedIn.value).toBe(false)
+    expect(isParentAuthenticated.value).toBe(false)
+  })
 })