add backend Docker dev service with hot reload.

Wire Nest into dev compose with src bind mount and health-check probe.

backend/Dockerfile.dev

@@ -0,0 +1,13 @@
+FROM node:20-alpine
+
+WORKDIR /backend
+
+RUN apk add --no-cache curl
+
+COPY package*.json .
+
+RUN npm ci
+
+COPY . .
+
+CMD ["npm", "run", "start:dev"]

docker-compose.dev.yml

@@ -30,6 +30,28 @@ services:
             postgres:
                 condition: service_healthy
 
+    backend:
+        build:
+            context: ./backend
+            dockerfile: Dockerfile.dev
+        container_name: ${COMPOSE_PROJECT_NAME}_backend
+        restart: unless-stopped
+        depends_on:
+            postgres:
+                condition: service_healthy
+        env_file:
+            - .env.dev
+        ports:
+            - '${BACKEND_PORT}:${BACKEND_PORT}'
+        volumes:
+            - ./backend/src:/backend/src
+        healthcheck:
+            test: ['CMD-SHELL', 'curl -f http://backend:${BACKEND_PORT}/api/health-check/']
+            interval: 1s
+            timeout: 30s
+            retries: 20
+            start_period: 10s
+
 volumes:
     private_image_postgres_data:
     private_image_pgadmin_data: