Add podman compose stack

compose.yaml

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+# Podman / Docker Compose stack for local hamprint development.
+#
+# Bring it up:   podman-compose up -d   (or: docker compose up -d)
+# Logs:          podman-compose logs -f web
+# Tear down:     podman-compose down            (keeps the pgdata volume)
+#                podman-compose down -v         (drops the pgdata volume too)
+#
+# The `web` service uses a stock python:3.14-slim image and bind-mounts this
+# repo at /app. On every start it installs from requirements.txt plus
+# psycopg[binary] (the pip-cache volume makes subsequent starts fast) and
+# runs Django's dev server. There is intentionally no Containerfile yet --
+# swap `image:` for `build: .` once Section 10's image lands.
+
+services:
+  db:
+    image: docker.io/library/postgres:16
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: ${POSTGRES_DB}
+      POSTGRES_USER: ${POSTGRES_USER}
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DB}"]
+      interval: 5s
+      timeout: 3s
+      retries: 10
+    env_file: .env
+
+  web:
+    image: docker.io/library/python:3.14-slim
+    working_dir: /app
+    command: >
+      bash -c "
+        pip install --quiet --no-input -r requirements.txt 'psycopg[binary]' &&
+        python manage.py migrate --noinput &&
+        python manage.py runserver 0.0.0.0:8000
+      "
+    env_file: .env
+    environment:
+      DJANGO_SETTINGS_MODULE: hamprint.settings.dev
+      DATABASE_URL: postgres://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}
+    ports:
+      - "8000:8000"
+    volumes:
+      - .:/app:Z
+      - pipcache:/root/.cache/pip
+    depends_on:
+      db:
+        condition: service_healthy
+
+volumes:
+  pgdata:
+  pipcache: