🧑‍💻(docker) split frontend to another file

This commit aims at improving the user experience:
- Use a dedicated `Dockerfile` for the frontend
- Run the backend and frontend in "watch"/dev mode in Docker
- Do not start all Docker instances for small tasks

src/backend/pyproject.toml

@@ -34,6 +34,7 @@ dependencies = [
     "django-configurations==2.5.1",
     "django-cors-headers==4.7.0",
     "django-countries==7.6.1",
+    "django-extensions==4.1",
     "django-lasuite==0.0.9",
     "django-oauth-toolkit==3.0.1",
     "django-parler==2.3",
@@ -70,7 +71,6 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
-    "django-extensions==4.1",
     "drf-spectacular-sidecar==2025.6.1",
     "ipdb==0.13.13",
     "ipython==9.3.0",