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>

plugin/sbin/podman-verify-packages.sh

@@ -34,7 +34,7 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 . "$SCRIPT_DIR/podman-common.sh"
 
 INSTALLED_VERSIONS_FILE="/usr/local/share/unraid-podman/installed-versions.env"
-PACKAGES="podman conmon crun netavark aardvark-dns passt fuse-overlayfs catatonit nftables docker-compose unraid-podman"
+PACKAGES="podman conmon crun netavark aardvark-dns passt fuse-overlayfs catatonit nftables podman-compose unraid-podman"
 
 QUIET=0
 [ "${1:-}" = "--quiet" ] && QUIET=1