fix(demo): use curl instead of PHP file_get_contents for PrestaShop healthcheck

[norbert-kulus-blockydevs]

Summary

• The prestashop service healthcheck reported unhealthy even when Apache/PrestaShop was serving fine, because PS_DOMAIN redirects / to the host-mapped port (localhost:8080), and PHP's file_get_contents() follows that redirect by default and fails with Connection refused from inside the container.
• Replaced with curl -fsS -o /dev/null http://localhost:80 (no -L), which accepts the 302 as proof the server is up, plus a comment explaining why -L must stay off.

Test plan

• Confirmed root cause live on a running openlinker-prestashop container (curl -L reproduces Failed to connect to localhost port 8080, file_get_contents returns the same Connection refused)
• Verified the new healthcheck command exits 0 against the live container
• pnpm dev:stack:up (or docker compose up -d prestashop) reaches healthy status on a fresh container recreate

Closes #1392

[piotrswierzy]

/pr-review — fix(demo): use curl for PrestaShop healthcheck

Summary

One-line healthcheck fix: PS_DOMAIN redirects / to http://localhost:8080 (the host-mapped port, unreachable from inside the container), and file_get_contents() follows that redirect and fails Connection refused — so PrestaShop was reported unhealthy while serving fine. Swaps to curl -fsS without -L, which treats the 302 as proof Apache is up. Approve.

Verified

• Root cause + fix are correct — accepting the 302 (no -L) is exactly right for a domain-redirect situation; following it (-L or file_get_contents's default) is the bug. The comment explains why -L must stay off, which will save the next reader from "fixing" it back. ✅
• curl is present in the PrestaShop image (author verified the new command exits 0 against the live container) — note this differs from the WooCommerce image in #1397, where curl is absent; the two healthchecks correctly use different tools for different images. ✅
• -fsS = fail-on-HTTP-error + silent + show-errors — the right flag set for a healthcheck probe.

Verdict

✅ Approve — minimal, correct, well-commented. The one unchecked box (fresh-recreate reaching healthy) is worth confirming on a clean dev:stack:up, but the live-container verification already proves the command semantics.