fix(installer): keep retrying readiness while the published port resets

[ttbombadil]

Problem

On a fresh Ubuntu 26.04 VM, scripts/install-ubuntu-vbox.sh aborted with "Der Backenddienst wurde gestartet, meldet aber keine Readiness".

Right after docker compose up -d, Docker's published port 127.0.0.1:3000 accepts connections and resets them until the backend listens (about 0.3 s later). curl reports that as exit 56, which neither --retry nor --retry-connrefused retries. The check gave up after one attempt, and the installation stopped before TLS and Nginx.

Reproduced on the VM 3/3 with the installer's curl options against a restarted container; 3/3 succeeded with --retry-all-errors. CI did not catch it because the deployment jobs use the renderer, not the installer script.

Change

• Both readiness checks (backend and HTTPS gateway) also pass --retry-all-errors. Nothing else in the installer or deployment changes.
• curl version: --retry-all-errors needs curl ≥ 7.71. Ubuntu 22.04 ships 7.81, 24.04 ships 8.5, 26.04 ships 8.18. The installer already requires docker-compose-v2 from these releases, so no documentation change is needed.

Regression test

tests/server/ubuntu-vbox-installer-readiness.test.ts reads the curl options of both readiness checks from the installer and runs them against a TCP server that resets the first connection (resetAndDestroy, a real RST).

Installer	Result
Fixed	both checks retry and return {"status":"ready"}
Old (main)	both checks fail with exit 56, same as on the VM

A further case documents that connection-refused retries alone give up after one reset.

Verification

• Targeted checks: the new test, ubuntu-vbox-capacity-defaults, scripts/test-install-ubuntu-vbox.sh, bash -n and shellcheck all pass.
• npm run check, ESLint, check:docs and git diff --check pass.
• ./run-tests.sh passes 11/11: Docker 32/32, E2E 27/27, Sonar gate PASSED with 0 violations.

🤖 Generated with Claude Code