[Infrastructure] Ingress 4GB body size limit & infinite wait in install script

[Flegma]

Summary

Ingress allows excessively large uploads and install script can hang.

Findings

• api/ingress.yaml — proxy-body-size: 4G. Demos endpoint unlimited (0).
• install_ingress_nginx.sh — fixed 60s wait with no max retry. Infinite loop possible.

Impact

Resource exhaustion from large uploads. Install script hangs forever.

Suggested Fix

Set reasonable limits (100M default, 2G demos). Add max retry counter to wait loop.