Implement Graceful Shutdown in server.js

[codeautopilot]

Resolves #9

Replace the use of process.exit() with a graceful shutdown process in the shutdown function to ensure all operations are completed before the application exits.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[deepsource-io]

Here's the code health analysis summary for commits bc03a25..4f22959. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
JavaScript	❌ Failure	❗ 2 occurences introduced 🎯 1 occurence resolved	View Check ↗

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