Fix port 8000 startup error

[NicoAgHerrera]

• A human has tested these changes.

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Why

When port 8000 is already in use, the ingress process fails, but the dev launcher can still report that the Agent Canvas stack started successfully. This is confusing because the main UI is served through the ingress port.

Summary

• Handle EADDRINUSE in scripts/ingress.mjs with a clear error message.
• Start ingress before the heavier backend/frontend services in the automation dev stack.
• Fail fast when the ingress port is unavailable instead of printing the success banner.

Issue Number

Fixes #899

How to Test

1. Start a process on port 8000:

   python -m http.server 8000

2. In another terminal, run:

   npm run dev

3. Confirm the command fails fast with a clear ingress port error.

4. Confirm it fails before starting agent-server, automation, or vite.

5. Confirm it does not print the Main UI: http://localhost:8000/ success banner.

I also tested the normal ingress startup path:

node scripts/ingress.mjs --port 8000 --default http://localhost:3001

with port 8000 free, and confirmed ingress starts normally.

Video/Screenshots

Not included; this is a CLI startup/error-handling fix.

Type

• Bug fix
• Feature
• Refactor
• Breaking change
• Docs / chore

Notes

Ingress is started first so port conflicts fail before spawning heavier backend/frontend services. ingress.mjs only binds the listening port and configures proxy routes, so it does not require target backends to be ready at startup.

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