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/lib/utils/tokenStorage.ts

@@ -61,12 +61,44 @@ export const tokenStorage = {
     }
   },
 
+  /**
+   * Get device ID from storage
+   */
+  getDeviceId: (): string | null => {
+    if (typeof window === 'undefined') {
+      return null;
+    }
+    try {
+      return localStorage.getItem('deviceId');
+    } catch (error) {
+      console.error('Error reading deviceId:', error);
+      return null;
+    }
+  },
+
+  /**
+   * Set device ID in storage
+   */
+  setDeviceId: (deviceId: string): void => {
+    if (typeof window === 'undefined') {
+      return;
+    }
+    try {
+      localStorage.setItem('deviceId', deviceId);
+    } catch (error) {
+      console.error('Error setting deviceId:', error);
+    }
+  },
+
   /**
    * Set both tokens at once
    */
-  setTokens: (accessToken: string, refreshToken: string): void => {
+  setTokens: (accessToken: string, refreshToken: string, deviceId?: string): void => {
     tokenStorage.setAccessToken(accessToken);
     tokenStorage.setRefreshToken(refreshToken);
+    if (deviceId) {
+      tokenStorage.setDeviceId(deviceId);
+    }
   },
 
   /**
@@ -79,6 +111,7 @@ export const tokenStorage = {
     try {
       localStorage.removeItem('accessToken');
       localStorage.removeItem('refreshToken');
+      localStorage.removeItem('deviceId');
     } catch (error) {
       console.error('Error clearing tokens:', error);
     }