- Dark / light mode a funcionar no lado do aluno

- Atualização dos ficheiros markdown.

docs/FRONTEND_MVP_TASKS.md

@@ -496,14 +496,20 @@ class FirebaseConstants {
 **Dependencies**: Task 1.4
 
 #### Subtasks:
-- [ ] Implement Firebase Auth service
-- [ ] Create user models and entities
-- [ ] Build authentication repository
-- [ ] Implement sign in use case
-- [ ] Implement sign up use case
+- [x] Implement Firebase Auth service
+- [x] Create user models and entities
+- [x] Build authentication repository
+- [x] Implement sign in use case
+- [x] Implement sign up use case
 - [ ] Implement password reset
-- [ ] Create authentication providers
-- [ ] Build login/signup screens
+- [x] Create authentication providers
+- [x] Build login/signup screens (with navigation improvements and theme fixes)
+
+**Recent Updates:**
+- ✅ Enhanced authentication navigation with PopScope for Android back button support
+- ✅ Removed AppBar and added custom positioned back button with aesthetic design
+- ✅ Fixed theme consistency in signup page input fields (light/dark mode)
+- ✅ Navigation flow complete: back button navigates to role-selection
 
 #### Implementation: