fix(healthcheck): use dynamic PORT, IPv4 127.0.0.1, and bind 0.0.0.0

Dockerfile

@@ -19,7 +19,7 @@ FROM node:22-alpine AS production
 WORKDIR /app
 
 ENV NODE_ENV=production \
-    PORT=3000
+    PORT=5000
 
 # Copy installed production dependencies and application code with proper ownership
 COPY --chown=node:node --from=dependencies /app/node_modules ./node_modules
@@ -28,10 +28,10 @@ COPY --chown=node:node . .
 # Run as non-root user
 USER node
 
-EXPOSE 3000
+EXPOSE 5000
 
 # Healthcheck targeting the API health endpoint
-HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
-  CMD wget --no-verbose --tries=1 --spider http://localhost:3000/api/health || exit 1
+HEALTHCHECK --interval=15s --timeout=5s --start-period=10s --retries=3 \
+  CMD wget --no-verbose --tries=1 --spider http://127.0.0.1:${PORT:-5000}/api/health || exit 1
 
 CMD ["node", "app.js"]