Add blueprints for authentication, admin, dashboard, gallery, generation, and profile routes

- Created `__init__.py` for blueprint registration.
- Implemented `auth.py` for user authentication (login, register, logout).
- Added `admin.py` for admin functionalities (user management, stats).
- Developed `dashboard.py` for user dashboard displaying user info and generated content.
- Created `gallery.py` for managing and displaying images and videos.
- Implemented `generate.py` for text, image, and video generation functionalities.
- Added `profile.py` for user profile management.
- Updated templates to reflect new route structures and improve navigation.

frontend/app/templates/login.html

@@ -11,6 +11,6 @@ endblock %} {% block content %}
 
     <button type="submit">Log in</button>
   </form>
-  <p>No account? <a href="{{ url_for('register') }}">Register</a></p>
+  <p>No account? <a href="{{ url_for('auth.register') }}">Register</a></p>
 </div>
 {% endblock %}