Replace vendored docker-compose with podman-compose

podman-compose and docker-compose aren't discovered the same way by
`podman compose` - verified live (a fake-binary test reading podman's own
provider-search error output) that docker-compose is searched for by
exact path across a fixed list of CLI-plugin directories, while
podman-compose is instead looked up as a plain command on $PATH. This
package installs to /usr/local/bin/podman-compose accordingly, not under
any cli-plugins/ directory.

Unlike docker-compose (a single static Go binary), podman-compose is a
Python script with two runtime dependencies neither of which ship with
Unraid's own Python3 - PyYAML and python-dotenv, vendored here as plain
pure-Python source (no C extension build; PyYAML's own fallback handles
its optional C accelerator being absent).

Verified end-to-end on a real host: with the previous docker-compose
binary temporarily moved aside to confirm podman-compose was actually the
one invoked, `podman compose up/ps/down` ran a real compose project
correctly, including a live HTTP check against the started service.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

packages/podman-compose/podman-compose.SlackBuild

@@ -0,0 +1,83 @@
+#!/bin/bash
+# =============================================================================
+# packages/podman-compose/podman-compose.SlackBuild
+#
+# Packages podman-compose (github.com/containers/podman-compose) — the
+# external "compose provider" `podman compose` shells out to (see
+# versions.env's PODMAN_COMPOSE_* block for the full story, including why
+# this replaces the project's earlier vendored docker-compose). Verified
+# live against a real podman install that podman-compose is looked up as a
+# plain $PATH command, unlike docker-compose's fixed CLI-plugin-directory
+# search — so this installs a wrapper at /usr/local/bin/podman-compose.
+#
+# podman-compose itself is a single Python script (not a compiled binary),
+# with two runtime dependencies — PyYAML and python-dotenv — vendored here
+# as plain pure-Python source (no C extension build) since Unraid ships
+# Python3 but neither of those modules.
+# =============================================================================
+
+set -eu
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+# shellcheck source=/dev/null
+. "$REPO_ROOT/scripts/lib/slackbuild-common.sh"
+# shellcheck source=/dev/null
+. "$REPO_ROOT/versions.env"
+
+VERSION="$PODMAN_COMPOSE_VERSION"
+ARCH="$PKG_ARCH"
+BUILD="$PKG_BUILD"
+TAG="$PKG_TAG"
+
+sb_init "podman-compose"
+
+script=$(sb_fetch_and_verify "$PODMAN_COMPOSE_SRC_URL" "$PODMAN_COMPOSE_SRC_SHA256" "podman_compose-$VERSION.py")
+pyyaml_tarball=$(sb_fetch_and_verify "$PYYAML_SRC_URL" "$PYYAML_SRC_SHA256" "pyyaml-$PYYAML_VERSION.tar.gz")
+dotenv_tarball=$(sb_fetch_and_verify "$PYTHON_DOTENV_SRC_URL" "$PYTHON_DOTENV_SRC_SHA256" "python-dotenv-$PYTHON_DOTENV_VERSION.tar.gz")
+
+libdir="$PKG/usr/local/lib/podman-compose"
+mkdir -p "$libdir"
+install -m 0644 "$script" "$libdir/podman_compose.py"
+
+# Only the pure-Python "yaml" package, not the "_yaml" C extension (which
+# would need libyaml plus a compiler toolchain this build doesn't otherwise
+# require) — see the header comment on why the pure-Python fallback is
+# sufficient for what podman-compose actually needs from it.
+tar -xzf "$pyyaml_tarball" -C "$TMP" "pyyaml-$PYYAML_VERSION/lib/yaml"
+cp -r "$TMP/pyyaml-$PYYAML_VERSION/lib/yaml" "$libdir/yaml"
+
+tar -xzf "$dotenv_tarball" -C "$TMP" "python_dotenv-$PYTHON_DOTENV_VERSION/src/dotenv"
+cp -r "$TMP/python_dotenv-$PYTHON_DOTENV_VERSION/src/dotenv" "$libdir/dotenv"
+
+# A thin wrapper, not a symlink or bare shebang: podman_compose.py's own
+# shebang (whatever upstream wrote, a plain "#!/usr/bin/env python3") has
+# no idea the vendored yaml/dotenv sit right next to it, so PYTHONPATH has
+# to be set by whatever actually invokes the script.
+install -d "$PKG/usr/local/bin"
+cat > "$PKG/usr/local/bin/podman-compose" <<'WRAPPER'
+#!/bin/sh
+exec env PYTHONPATH="/usr/local/lib/podman-compose${PYTHONPATH:+:$PYTHONPATH}" \
+  /usr/bin/python3 /usr/local/lib/podman-compose/podman_compose.py "$@"
+WRAPPER
+chmod 0755 "$PKG/usr/local/bin/podman-compose"
+
+docdir="$PKG/usr/doc/podman-compose-$VERSION"
+mkdir -p "$docdir"
+{
+  echo "podman-compose $VERSION"
+  echo "https://github.com/containers/podman-compose"
+  echo
+  echo "Vendored alongside its two runtime dependencies (bundled as plain"
+  echo "pure-Python source, no C extensions built):"
+  echo "  PyYAML $PYYAML_VERSION - https://pypi.org/project/PyYAML/"
+  echo "  python-dotenv $PYTHON_DOTENV_VERSION - https://pypi.org/project/python-dotenv/"
+  echo
+  echo "See versions.env for pinned source URLs and SHA256 checksums."
+} > "$docdir/README"
+{
+  echo "Built by unraid-podman from upstream source."
+  echo "Package: podman-compose $VERSION"
+  echo "Built:   $(date -u +%Y-%m-%dT%H:%M:%SZ)"
+} > "$docdir/unraid-podman.build-info"
+
+sb_make_package "$VERSION" "$ARCH" "$BUILD" "$TAG"