Fix ssh/scp/sftp for containers running as a uid without passwd entry

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docker/ssh-nss

@@ -0,0 +1,13 @@
+#!/bin/sh
+# ssh, scp and sftp for containers that run as an arbitrary uid (docker-compose `user:`):
+# OpenSSH refuses to start without a passwd entry for the uid ("No user exists for uid N").
+# Without an entry, nss_wrapper provides one for this process; otherwise nothing changes.
+if ! getent passwd "$(id -u)" >/dev/null 2>&1; then
+  d=${TMPDIR:-/tmp}/codecraft-nss-$(id -u)
+  mkdir -p "$d" 2>/dev/null
+  printf 'codecraft:x:%s:%s:CodeCraft:%s:/bin/sh\n' "$(id -u)" "$(id -g)" "${HOME:-/}" > "$d/passwd"
+  printf 'codecraft:x:%s:\n' "$(id -g)" > "$d/group"
+  export NSS_WRAPPER_PASSWD="$d/passwd" NSS_WRAPPER_GROUP="$d/group"
+  export LD_PRELOAD="libnss_wrapper.so${LD_PRELOAD:+:$LD_PRELOAD}"
+fi
+exec "/usr/bin/$(basename "$0")" "$@"