update compose for monorepo

.build/dev/Dockerfile

@@ -0,0 +1,13 @@
+FROM python:3.12-slim
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1
+
+WORKDIR /app
+
+# Source is bind-mounted at runtime; (re)install deps on start so
+# requirements.txt changes are picked up without a rebuild, then run the
+# Django autoreloading dev server.
+CMD pip install --no-cache-dir -r requirements.txt \
+ && python manage.py migrate \
+ && python manage.py runserver 0.0.0.0:5000