feat(jenkins): Add Docker CLI installation script

apps/jenkins/scripts/install-docker.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+# Jenkins initialization script to install Docker CLI
+
+set -e
+
+echo "Installing Docker CLI in Jenkins..."
+
+# Update package list
+apt-get update
+
+# Install prerequisites
+apt-get install -y \
+    ca-certificates \
+    curl \
+    gnupg \
+    lsb-release
+
+# Add Docker's official GPG key
+mkdir -p /etc/apt/keyrings
+curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg
+
+# Set up repository
+echo \
+  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian \
+  $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null
+
+# Install Docker CLI only (not daemon)
+apt-get update
+apt-get install -y docker-ce-cli
+
+# Verify installation
+docker --version
+
+# Add jenkins user to docker group (if group exists on host)
+usermod -aG docker jenkins || true
+
+echo "✅ Docker CLI installed successfully!"