fix: build the Backend image as glibc so it can load libssl [CI]

The musl AotAnywhere output is a fully static executable, which cannot dlopen libssl: the Backend exited with 'No usable version of libssl was found' on start. Use linux-x64/arm64 and the Debian runtime-deps base.

ci/release-linux.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
-# Build a musl NativeAOT Backend OCI image with statically linked SQLite; publishing is optional.
+# Build a glibc NativeAOT Backend OCI image with statically linked SQLite; publishing is optional.
+# glibc and a dynamic executable are required: the musl AotAnywhere output is fully static and cannot dlopen libssl, so the signing code fails at startup.
 set -euo pipefail
 
 arch="${1:?usage: release-linux.sh <amd64|arm64>}"
@@ -28,8 +29,8 @@ if [[ "$image_publish" == true ]]; then
   }
 fi
 case "$arch" in
-  amd64) rid=linux-musl-x64 ;;
-  arm64) rid=linux-musl-arm64 ;;
+  amd64) rid=linux-x64 ;;
+  arm64) rid=linux-arm64 ;;
   *) echo "unsupported architecture: $arch" >&2; exit 2 ;;
 esac