fix: broken healthchecks on sh containers (#4300)

healthcheck.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 curlCheck() {
   if ! curl -s --head "$1" | head -n 1 | grep -q "HTTP/1.[01] [23].."; then

prod.Dockerfile

@@ -119,8 +119,8 @@ COPY aio-subpath-access.Caddyfile /etc/caddy/aio-subpath-access.Caddyfile
 RUN npm install -g @import-meta-env/cli
 
 ENTRYPOINT [ "tini", "--" ]
-COPY --chmod=755 healthcheck.sh .
-HEALTHCHECK --interval=2s CMD /bin/sh ./healthcheck.sh
+COPY --chmod=755 healthcheck.sh /
+HEALTHCHECK --interval=2s CMD /bin/sh /healthcheck.sh
 
 WORKDIR /dist/backend