fix: update dev environment ports

docker-compose.dev.yml

@@ -5,8 +5,8 @@
 #
 # To start both, run: docker compose -f docker-compose.dev.yml up
 #
-# Your site will be available at http://localhost:8080
-# Your API will be available at http://localhost:3000
+# Your site will be available at http://localhost:8080.
+# API requests are proxied from /api to the API service, so you don't need to access port 3000 directly.
 services:
   # This service runs the Eleventy development server.
   eleventy:
@@ -42,8 +42,9 @@ services:
     # to detach cleanly.
     init: true
     container_name: api_dev
+    # The API port does not need to be exposed to the host. The 'eleventy'
+    # service proxies requests to it over the internal Docker network.
     ports:
-      - "3000:3000" # Express API server port
       - "9229:9229" # Node.js debugger port
     volumes:
       - .:/app