Fix session persistence issue

- Created SSR-safe tokenStorage utility for localStorage access
- Updated AuthContext with window availability checks
- Enhanced API client interceptors with SSR safety
- Improved error handling to only clear tokens on auth errors (401/403)
- Added token refresh support for multiple response structures
- Added redirect loop prevention in auth flow

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

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

maternal-web/lib/utils/tokenStorage.ts

@@ -0,0 +1,93 @@
+/**
+ * Safe token storage utilities that work with both SSR and client-side rendering
+ */
+
+export const tokenStorage = {
+  /**
+   * Get access token from storage
+   */
+  getAccessToken: (): string | null => {
+    if (typeof window === 'undefined') {
+      return null;
+    }
+    try {
+      return localStorage.getItem('accessToken');
+    } catch (error) {
+      console.error('Error reading accessToken:', error);
+      return null;
+    }
+  },
+
+  /**
+   * Get refresh token from storage
+   */
+  getRefreshToken: (): string | null => {
+    if (typeof window === 'undefined') {
+      return null;
+    }
+    try {
+      return localStorage.getItem('refreshToken');
+    } catch (error) {
+      console.error('Error reading refreshToken:', error);
+      return null;
+    }
+  },
+
+  /**
+   * Set access token in storage
+   */
+  setAccessToken: (token: string): void => {
+    if (typeof window === 'undefined') {
+      return;
+    }
+    try {
+      localStorage.setItem('accessToken', token);
+    } catch (error) {
+      console.error('Error setting accessToken:', error);
+    }
+  },
+
+  /**
+   * Set refresh token in storage
+   */
+  setRefreshToken: (token: string): void => {
+    if (typeof window === 'undefined') {
+      return;
+    }
+    try {
+      localStorage.setItem('refreshToken', token);
+    } catch (error) {
+      console.error('Error setting refreshToken:', error);
+    }
+  },
+
+  /**
+   * Set both tokens at once
+   */
+  setTokens: (accessToken: string, refreshToken: string): void => {
+    tokenStorage.setAccessToken(accessToken);
+    tokenStorage.setRefreshToken(refreshToken);
+  },
+
+  /**
+   * Clear all tokens from storage
+   */
+  clearTokens: (): void => {
+    if (typeof window === 'undefined') {
+      return;
+    }
+    try {
+      localStorage.removeItem('accessToken');
+      localStorage.removeItem('refreshToken');
+    } catch (error) {
+      console.error('Error clearing tokens:', error);
+    }
+  },
+
+  /**
+   * Check if user has valid tokens
+   */
+  hasTokens: (): boolean => {
+    return !!(tokenStorage.getAccessToken() && tokenStorage.getRefreshToken());
+  },
+};