Update Dockerfile entrypoint to use node directly

[qtomlinson]

Overview
This PR improves Docker container behavior by replacing the npm-based entrypoint with direct Node.js execution, enabling proper signal handling and graceful container shutdown.

Background:
the server fails to start with the following error:

2025-12-17T06:31:53.7248178Z npm ERR! path /opt/service
2025-12-17T06:31:53.7249081Z npm ERR! command failed
2025-12-17T06:31:53.7251978Z npm ERR! signal SIGTERM
2025-12-17T06:31:53.7254913Z npm ERR! command sh -c "node --max-old-space-size=8192 ./bin/www"
2025-12-17T06:31:53.7336171Z npm ERR! A complete log of this run can be found in: /root/.npm/_logs/2025-12-17T06_28_02_218Z-debug-0.log

The issue is likely caused by the memory allocation setting: the process is requesting 8GB, which exceeds the 7GB provisioned on our dev App Service Plan. This is a known issue tracked at #1256.

Key Changes:

• Entrypoint Update
• Memory Configuration: Added ENV NODE_OPTIONS="--max-old-space-size=8192" for configurable memory allocation. We can potentially set this to a lower value on dev deployment.

[ryanbrandenburg]

This looks like a good near-term fix, though I wonder what the long-term objects being retained are.

[qtomlinson]

@ryanbrandenburg Thank you for the feedback. This PR provides a short‑term measure to get the service running, and it also introduces two improvements:

• Running the app with node directly (instead of npm start or a wrapper) ensures signals like SIGTERM/SIGINT reach the process, enabling graceful shutdown.
• NODE_OPTIONS is the official Node.js runtime configuration mechanism; it lets you adjust settings (e.g., --max-old-space-size) without code changes or rebuilds.