fix: Comprehensive authentication and UI fixes

Authentication & Token Management:
- Add deviceId to token refresh flow (backend requires both refreshToken and deviceId)
- Fix React Strict Mode token clearing race condition with retry logic
- Improve AuthContext to handle all token state combinations properly
- Store deviceId in localStorage alongside tokens

UI/UX Improvements:
- Remove deprecated legacyBehavior from Next.js Link components
- Update primary theme color to WCAG AA compliant #7c3aed
- Fix nested button error in TabBar voice navigation
- Fix invalid Tabs value error in DynamicChildDashboard

Multi-Child Dashboard:
- Load all children into Redux store properly
- Fetch metrics for all children, not just selected one
- Remove mock data to prevent unauthorized API calls

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

maternal-web/store/slices/childrenSlice.ts

@@ -91,45 +91,18 @@ interface ChildrenState {
   lastSyncTime: string | null;
 }
 
-// Mock children for development (matches real data from andrei@cloudz.ro)
-const MOCK_CHILDREN: Child[] = process.env.NODE_ENV === 'development' ? [
-  {
-    id: 'child_alice123',
-    familyId: 'fam_test123',
-    name: 'Alice',
-    birthDate: '2023-03-15',
-    gender: 'female',
-    displayColor: '#FF6B9D',
-    sortOrder: 1,
-    createdAt: new Date().toISOString(),
-  },
-  {
-    id: 'child_bob456',
-    familyId: 'fam_test123',
-    name: 'Bob',
-    birthDate: '2024-06-20',
-    gender: 'male',
-    displayColor: '#4A90E2',
-    sortOrder: 2,
-    createdAt: new Date().toISOString(),
-  },
-] : [];
-
 const childrenSlice = createSlice({
   name: 'children',
-  initialState: childrenAdapter.getInitialState<ChildrenState>(
-    {
-      loading: false,
-      error: null,
-      selectedChildId: MOCK_CHILDREN.length > 0 ? MOCK_CHILDREN[0].id : null,
-      selectedChildIds: MOCK_CHILDREN.length > 0 ? [MOCK_CHILDREN[0].id] : [],
-      defaultChildId: MOCK_CHILDREN.length > 0 ? MOCK_CHILDREN[0].id : null,
-      viewMode: 'auto',
-      lastSelectedPerScreen: {},
-      lastSyncTime: null,
-    },
-    MOCK_CHILDREN
-  ),
+  initialState: childrenAdapter.getInitialState<ChildrenState>({
+    loading: false,
+    error: null,
+    selectedChildId: null,
+    selectedChildIds: [],
+    defaultChildId: null,
+    viewMode: 'auto',
+    lastSelectedPerScreen: {},
+    lastSyncTime: null,
+  }),
   reducers: {
     // Optimistic operations
     optimisticCreate: (state, action: PayloadAction<Child>) => {