feat: implement user profile management (Fase 2)

- Add useProfile hook for managing user data
- Add Profile page to view/edit user information
- Add Settings layout with sidebar navigation
- Add Settings pages: Profile, Password, Notifications, Account
- Add user dropdown menu in Header with Profile/Settings links
- Add protected routes for /settings/* pages
- Implement profile update and password change functionality

Completes Fase 2 of frontend missing features analysis from todo.md

frontend/src/hooks/useProfile.ts

@@ -0,0 +1,109 @@
+import { useState, useEffect, useCallback } from 'react';
+import api from '@/lib/api';
+import { showToast } from '@/components/ui/toast-utils';
+
+export interface User {
+  id: string;
+  email: string;
+  full_name: string;
+  is_active: boolean;
+  created_at: string;
+}
+
+export function useProfile() {
+  const [user, setUser] = useState<User | null>(null);
+  const [loading, setLoading] = useState<boolean>(true);
+  const [error, setError] = useState<string | null>(null);
+
+  // Fetch user profile
+  const getProfile = useCallback(async () => {
+    setLoading(true);
+    setError(null);
+    try {
+      const response = await api.get('/auth/me');
+      const userData = response.data;
+      setUser(userData);
+      return userData;
+    } catch (err: any) {
+      const message = err.response?.data?.detail || 'Failed to load profile';
+      setError(message);
+      showToast({
+        title: 'Error loading profile',
+        description: message,
+        variant: 'destructive'
+      });
+      return null;
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  // Update user profile
+  const updateProfile = useCallback(async (data: Partial<User>) => {
+    setLoading(true);
+    setError(null);
+    try {
+      const response = await api.put('/auth/me', data);
+      const updatedUser = response.data;
+      setUser(updatedUser);
+      showToast({
+        title: 'Profile updated',
+        description: 'Your profile has been successfully updated'
+      });
+      return updatedUser;
+    } catch (err: any) {
+      const message = err.response?.data?.detail || 'Failed to update profile';
+      setError(message);
+      showToast({
+        title: 'Update failed',
+        description: message,
+        variant: 'destructive'
+      });
+      throw err;
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  // Change password
+  const changePassword = useCallback(async (passwordData: {
+    current_password: string;
+    new_password: string;
+  }) => {
+    setLoading(true);
+    setError(null);
+    try {
+      await api.post('/auth/change-password', passwordData);
+      showToast({
+        title: 'Password changed',
+        description: 'Your password has been successfully updated'
+      });
+      return true;
+    } catch (err: any) {
+      const message = err.response?.data?.detail || 'Failed to change password';
+      setError(message);
+      showToast({
+        title: 'Password change failed',
+        description: message,
+        variant: 'destructive'
+      });
+      throw err;
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  // Load profile on mount
+  useEffect(() => {
+    getProfile();
+  }, [getProfile]);
+
+  return {
+    user,
+    loading,
+    error,
+    getProfile,
+    updateProfile,
+    changePassword
+  };
+}