validação entre professor e aluno, criação de placeholder para a tela de professores e mudanças na firebase

lib/features/auth/presentation/pages/role_selection_page.dart

@@ -278,6 +278,28 @@ class _RoleSelectionPageState extends State<RoleSelectionPage> {
                         ),
 
                     const SizedBox(height: 32),
+
+                    // Login link
+                    GestureDetector(
+                      onTap: _selectedRole != null ? _handleGoToLogin : null,
+                      child: Text(
+                        'Já tenho conta',
+                        style: TextStyle(
+                          color: _selectedRole != null
+                              ? AppColors.primaryBlue
+                              : Colors.grey,
+                          fontWeight: FontWeight.w500,
+                          decoration: TextDecoration.underline,
+                        ),
+                      ),
+                    )
+                        .animate()
+                        .fadeIn(
+                      duration: const Duration(milliseconds: 800),
+                      delay: const Duration(milliseconds: 1400),
+                    ),
+
+                    const SizedBox(height: 32),
                   ],
                 ),
               ),
@@ -288,6 +310,12 @@ class _RoleSelectionPageState extends State<RoleSelectionPage> {
     );
   }
 
+  void _handleGoToLogin() {
+    if (_selectedRole != null) {
+      context.go('/login?role=$_selectedRole');
+    }
+  }
+
   Widget _buildRoleCard(
     BuildContext context,
     String title,