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/build/build-image-missing.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+source "${SCRIPT_DIR}/resolve-base-image.sh"
+
+echo "============================================================"
+echo ">>> Building ONLY missing container images"
+echo "============================================================"
+
+for distro in $DISTROS; do
+    IMAGE="package-manager-test-$distro"
+    BASE_IMAGE="$(resolve_base_image "$distro")"
+
+    if docker image inspect "$IMAGE" >/dev/null 2>&1; then
+        echo "[build-missing] Image already exists: $IMAGE (skipping)"
+        continue
+    fi
+
+    echo
+    echo "------------------------------------------------------------"
+    echo "[build-missing] Building missing image: $IMAGE"
+    echo "BASE_IMAGE = $BASE_IMAGE"
+    echo "------------------------------------------------------------"
+
+    docker build \
+        --build-arg BASE_IMAGE="$BASE_IMAGE" \
+        -t "$IMAGE" \
+        .
+done
+
+echo
+echo "============================================================"
+echo ">>> build-missing: Done"
+echo "============================================================"