Refactor container build and installation pipeline to use configurable Makefile parameters (e.g. DISTROS, base images) and propagate them through all build, install, and test scripts

scripts/pkgmgr-wrapper.sh

@@ -1,10 +1,40 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
+# Ensure NIX_CONFIG has our defaults if not already set
 if [[ -z "${NIX_CONFIG:-}" ]]; then
   export NIX_CONFIG="experimental-features = nix-command flakes"
 fi
 
 FLAKE_DIR="/usr/lib/package-manager"
 
-exec nix run "${FLAKE_DIR}#pkgmgr" -- "$@"
+# ------------------------------------------------------------
+# Try to ensure that "nix" is on PATH
+# ------------------------------------------------------------
+if ! command -v nix >/dev/null 2>&1; then
+  # Common locations for Nix installations
+  CANDIDATES=(
+    "/nix/var/nix/profiles/default/bin/nix"
+    "${HOME:-/root}/.nix-profile/bin/nix"
+  )
+
+  for candidate in "${CANDIDATES[@]}"; do
+    if [[ -x "$candidate" ]]; then
+      # Prepend the directory of the candidate to PATH
+      PATH="$(dirname "$candidate"):${PATH}"
+      export PATH
+      break
+    fi
+  done
+fi
+
+# ------------------------------------------------------------
+# Primary (and only) path: use Nix flake if available
+# ------------------------------------------------------------
+if command -v nix >/dev/null 2>&1; then
+  exec nix run "${FLAKE_DIR}#pkgmgr" -- "$@"
+fi
+
+echo "[pkgmgr-wrapper] ERROR: 'nix' binary not found on PATH."
+echo "[pkgmgr-wrapper] Nix is required to run pkgmgr (no Python fallback)."
+exit 1