Apply @appcypher's recommendations for microsandbox Docker configuration

Co-authored-by: Sun-ZhenXing <44517244+Sun-ZhenXing@users.noreply.github.com>

builds/microsandbox/.env.example

@@ -2,29 +2,51 @@
 # KVM-based secure sandbox environment
 
 # Global registry prefix (optional)
-# Leave empty to pull from Docker Hub
+# Leave empty to use ghcr.io/zerocore-ai/microsandbox
 GLOBAL_REGISTRY=
 
 # MicroSandbox version
-# Default: 0.2.6
-MICROSANDBOX_VERSION=0.2.6
+# Default: latest (recommended to use latest stable version)
+# Set to empty string to always pull the latest version
+MICROSANDBOX_VERSION=latest
 
-# Auto pull base images on build
+# Debian base image version
+# Default: 13.2-slim
+DEBIAN_VERSION=13.2-slim
+
+# Auto pull base images on build (Python, Node.js SDKs)
 # Default: true
 MICROSANDBOX_AUTO_PULL_IMAGES=true
 
+# Development mode (disables API key requirements)
+# Default: true (for easier testing)
+# Set to false in production environments
+MICROSANDBOX_DEV_MODE=true
+
 # Timezone
 # Default: UTC
 TZ=UTC
 
+# ============================================
+# Port Configuration
+# ============================================
+
+# Internal port (inside container)
+# Default: 5555
+MICROSANDBOX_PORT=5555
+
+# External port (host machine)
+# Default: 5555
+MICROSANDBOX_PORT_OVERRIDE=5555
+
 # ============================================
 # Resource Limits
 # ============================================
 
 # CPU limits
 # MicroSandbox requires more CPU for KVM virtualization
-MICROSANDBOX_CPU_LIMIT=4.00
-MICROSANDBOX_CPU_RESERVATION=1.00
+MICROSANDBOX_CPU_LIMIT=4
+MICROSANDBOX_CPU_RESERVATION=1
 
 # Memory limits
 # MicroSandbox requires more memory for running VMs