feat(installers): add Docker CLI plugin installer

Add docker_plugin.sh for installing Docker CLI plugins (compose, buildx)
from GitHub releases. Downloads and installs plugins to ~/.docker/cli-plugins/.

Changes:
- Add scripts/installers/docker_plugin.sh for plugin installation
- Add plugin_name field to catalog/compose.json for Docker plugins

Author: CybotTM

catalog/compose.json

@@ -5,6 +5,7 @@
   "homepage": "https://docs.docker.com/compose/",
   "github_repo": "docker/compose",
   "binary_name": "docker",
+  "plugin_name": "compose",
   "version_command": "docker compose version 2>&1 | head -1",
   "notes": "Docker Compose v2 is a plugin for Docker CLI. Can be installed separately as a plugin or bundled with Docker Desktop."
 }

scripts/installers/docker_plugin.sh

@@ -0,0 +1,106 @@
+#!/usr/bin/env bash
+# Installer for Docker CLI plugins (e.g., compose, buildx)
+# Installs plugins to ~/.docker/cli-plugins/
+set -euo pipefail
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+. "$DIR/lib/common.sh"
+. "$DIR/lib/install_strategy.sh"
+
+TOOL="${1:-}"
+if [ -z "$TOOL" ]; then
+  echo "Usage: $0 TOOL_NAME" >&2
+  exit 1
+fi
+
+CATALOG_FILE="$DIR/../catalog/$TOOL.json"
+if [ ! -f "$CATALOG_FILE" ]; then
+  echo "Error: Catalog file not found: $CATALOG_FILE" >&2
+  exit 1
+fi
+
+# Parse catalog
+BINARY_NAME="$(jq -r '.binary_name' "$CATALOG_FILE")"
+GITHUB_REPO="$(jq -r '.github_repo // empty' "$CATALOG_FILE")"
+PLUGIN_NAME="$(jq -r '.plugin_name // .name' "$CATALOG_FILE")"
+VERSION_COMMAND="$(jq -r '.version_command // empty' "$CATALOG_FILE")"
+
+# Docker CLI plugins go to ~/.docker/cli-plugins/
+PLUGIN_DIR="$HOME/.docker/cli-plugins"
+mkdir -p "$PLUGIN_DIR"
+
+# Get current version
+before=""
+if [ -n "$VERSION_COMMAND" ]; then
+  before="$(eval "$VERSION_COMMAND" 2>/dev/null || true)"
+elif [ -f "$PLUGIN_DIR/docker-$PLUGIN_NAME" ]; then
+  before="$(docker $PLUGIN_NAME version 2>/dev/null | head -1 || true)"
+fi
+
+# Detect OS and architecture
+OS="$(uname -s | tr '[:upper:]' '[:lower:]')"
+ARCH_RAW="$(uname -m)"
+
+# Map architecture to Docker's naming convention
+case "$ARCH_RAW" in
+  x86_64)  ARCH="x86_64" ;;
+  aarch64) ARCH="aarch64" ;;
+  arm64)   ARCH="aarch64" ;;
+  armv7l)  ARCH="armv7" ;;
+  armv6l)  ARCH="armv6" ;;
+  *)       ARCH="$ARCH_RAW" ;;
+esac
+
+# Resolve latest version from GitHub
+LATEST=""
+if [ -n "$GITHUB_REPO" ]; then
+  LATEST="$(curl -fsSIL -H "User-Agent: cli-audit" -o /dev/null -w '%{url_effective}' \
+    "https://github.com/$GITHUB_REPO/releases/latest" 2>/dev/null | awk -F'/' '{print $NF}')"
+fi
+
+if [ -z "$LATEST" ]; then
+  echo "[$TOOL] Error: Unable to resolve latest version" >&2
+  echo "[$TOOL] before: ${before:-<none>}" >&2
+  exit 1
+fi
+
+# Build download URL
+# Docker Compose uses: docker-compose-{os}-{arch}
+DOWNLOAD_URL="https://github.com/$GITHUB_REPO/releases/download/$LATEST/docker-$PLUGIN_NAME-$OS-$ARCH"
+
+# Download
+tmpfile="/tmp/docker-$PLUGIN_NAME.$$"
+rm -f "$tmpfile"
+
+echo "[$TOOL] Downloading $DOWNLOAD_URL"
+if ! curl -fL --retry 3 --retry-delay 1 --connect-timeout 10 -o "$tmpfile" "$DOWNLOAD_URL" 2>/dev/null; then
+  echo "[$TOOL] Error: Download failed from $DOWNLOAD_URL" >&2
+  rm -f "$tmpfile"
+  exit 1
+fi
+
+# Validate download
+if ! [ -s "$tmpfile" ]; then
+  echo "[$TOOL] Error: Downloaded file is empty" >&2
+  rm -f "$tmpfile"
+  exit 1
+fi
+
+# Install to Docker CLI plugins directory
+chmod +x "$tmpfile"
+mv "$tmpfile" "$PLUGIN_DIR/docker-$PLUGIN_NAME"
+
+# Report
+after=""
+if [ -n "$VERSION_COMMAND" ]; then
+  after="$(eval "$VERSION_COMMAND" 2>/dev/null || true)"
+else
+  after="$(docker $PLUGIN_NAME version 2>/dev/null | head -1 || true)"
+fi
+
+printf "[%s] before: %s\n" "$TOOL" "${before:-<none>}"
+printf "[%s] after:  %s\n" "$TOOL" "${after:-<none>}"
+printf "[%s] path:   %s\n" "$TOOL" "$PLUGIN_DIR/docker-$PLUGIN_NAME"
+
+# Refresh snapshot after successful installation
+refresh_snapshot "$TOOL"