1-hour workshop: Fail startup clearly when dependencies or services do not start

Problem

The learner setup depends entirely on the startup scripts, but failure handling can report a misleading success state. In app/scripts/start-app.sh, npm install is not checked before npm run dev starts. In app/scripts/start-app.ps1, a failed Node dependency installation emits a warning and continues. Both scripts wait a fixed five seconds and then print both service URLs without checking that Flask and Astro are ready.

This makes common setup failures look like browser or workshop problems and gives independent learners little actionable feedback.

Suggested change

Make both startup scripts stop on dependency installation failures and verify service/process readiness before announcing success.

Acceptance criteria

• A failed Python or Node dependency install exits nonzero with a clear message.
• Failure of either Flask or Astro stops the other managed process.
• URLs are printed only after both services are ready.
• Cleanup still works on Ctrl+C and partial startup failures.
• macOS/Linux and Windows paths have equivalent behavior.

Inizia con app/scripts/start-app.sh e app/scripts/start-app.ps1, seguendo l’installazione delle dipendenze, l’attesa fissa di cinque secondi, l’output degli URL dei servizi e i percorsi di pulizia. Esegui entrambi gli script di avvio simulando un’installazione non riuscita di Python o Node e un avvio non riuscito di Flask o Astro; il lavoro è completato quando gli errori hanno uno stato diverso da zero e chiaro, i processi gestiti si arrestano insieme, gli URL vengono visualizzati solo dopo che entrambi i servizi sono pronti e la pulizia continua a funzionare con Ctrl+C o dopo un avvio parziale.