Document Docker image variants and Python migration

Sync documentation for PR #259: Optimize Docker image size with lean and Python variants

Changes:
- Add documentation for two image variants (default and -python)
- Include breaking change notice for Python users
- Add migration guide from v0.5.x to v0.6.0+
- Document PYTHON_NOT_AVAILABLE error behavior
- Update all examples to show appropriate image selection
- Clarify Python availability requirements in Code Interpreter API

Related upstream PR: cloudflare/sandbox-sdk#259

Author: github-actions[bot]

src/content/docs/sandbox/api/interpreter.mdx

@@ -9,6 +9,16 @@ import { TypeScriptExample } from "~/components";
 
 Execute Python, JavaScript, and TypeScript code with support for data visualizations, tables, and rich output formats. Contexts maintain state (variables, imports, functions) across executions.
 
+:::note[Python execution requires Python image]
+To execute Python code, you must use the `-python` image variant in your Dockerfile:
+
+```dockerfile
+FROM docker.io/cloudflare/sandbox:0.6.0-python
+```
+
+The default image only supports JavaScript and TypeScript. Attempting to run Python code without the Python image will fail with a `PYTHON_NOT_AVAILABLE` error. See [Dockerfile reference](/sandbox/configuration/dockerfile/) for details on image variants.
+:::
+
 ## Methods
 
 ### `createCodeContext()`

src/content/docs/sandbox/concepts/containers.mdx

@@ -5,14 +5,14 @@ sidebar:
   order: 3
 ---
 
-Each sandbox runs in an isolated Linux container with Python, Node.js, and common development tools pre-installed. For a complete list of pre-installed software and how to customize the container image, see [Dockerfile reference](/sandbox/configuration/dockerfile/).
+Each sandbox runs in an isolated Linux container with Node.js and common development tools pre-installed. Two image variants are available: a lean default image for shell and JavaScript workloads, and a Python-enabled image for data science tasks. For a complete list of pre-installed software and how to customize the container image, see [Dockerfile reference](/sandbox/configuration/dockerfile/).
 
 ## Runtime software installation
 
 Install additional software at runtime using standard package managers:
 
 ```bash
-# Python packages
+# Python packages (requires Python image variant)
 pip install scikit-learn tensorflow
 
 # Node.js packages
@@ -22,6 +22,10 @@ npm install express
 apt-get update && apt-get install -y redis-server
 ```
 
+:::note[Python package installation]
+Python package installation requires the `-python` image variant. See [Dockerfile reference](/sandbox/configuration/dockerfile/) for details on choosing the appropriate image variant.
+:::
+
 ## Filesystem
 
 The container provides a standard Linux filesystem. You can read and write anywhere you have permissions.

src/content/docs/sandbox/configuration/dockerfile.mdx

@@ -9,35 +9,81 @@ Customize the sandbox container image with your own packages, tools, and configu
 
 ## Base image
 
-The Sandbox SDK uses a Ubuntu-based Linux container with Python, Node.js (via Bun), and common development tools pre-installed:
+The Sandbox SDK provides two image variants: a lean image for shell and JavaScript workloads, and a Python-enabled image for data science and machine learning tasks.
+
+### Image variants
+
+**Default (lean)** - Shell and JavaScript/TypeScript execution (~600-800MB):
 
 ```dockerfile
 FROM docker.io/cloudflare/sandbox:0.3.3
 ```
 
-:::caution[Version synchronization required]
-Always match the Docker image version to your npm package version. If you're using `@cloudflare/sandbox@0.3.3`, use `docker.io/cloudflare/sandbox:0.3.3` as your base image.
+**Python variant** - Includes Python with data science packages (~1.3GB):
+
+```dockerfile
+FROM docker.io/cloudflare/sandbox:0.3.3-python
+```
+
+:::caution[Breaking change for Python users]
+**Version 0.6.0+ requires explicit Python image**
+
+Starting with version 0.6.0, the default image no longer includes Python. If you use the [Code Interpreter API](/sandbox/api/interpreter/) to run Python code, you must use the `-python` image variant.
+
+**Migration required:**
+
+```dockerfile
+# Before (v0.5.x)
+FROM docker.io/cloudflare/sandbox:0.5.6
+
+# After (v0.6.0+)
+FROM docker.io/cloudflare/sandbox:0.6.0-python
+```
+
+Without this change, Python execution will fail with a `PYTHON_NOT_AVAILABLE` error.
+:::
+
+:::note[Version synchronization required]
+Always match the Docker image version to your npm package version. If you are using `@cloudflare/sandbox@0.3.3`, use `docker.io/cloudflare/sandbox:0.3.3` (or `0.3.3-python`) as your base image.
 
-**Why this matters**: The SDK automatically checks version compatibility on startup. Mismatched versions can cause features to break or behave unexpectedly. If versions don't match, you'll see warnings in your logs.
+**Why this matters**: The SDK automatically checks version compatibility on startup. Mismatched versions can cause features to break or behave unexpectedly. If versions do not match, you will see warnings in your logs.
 
 See [Version compatibility](/sandbox/concepts/sandboxes/#version-compatibility) for troubleshooting version mismatch warnings.
 :::
 
-**What's included:**
+### What's included
+
+**Default image includes:**
 
 - Ubuntu 22.04 LTS base
-- Python 3.11.14 with pip and venv
 - Node.js 20 LTS with npm
 - Bun 1.x (JavaScript/TypeScript runtime)
-- Pre-installed Python packages: matplotlib, numpy, pandas, ipython
 - System utilities: curl, wget, git, jq, zip, unzip, file, procps, ca-certificates
 
+**Python image adds:**
+
+- Python 3.11.14 with pip and venv
+- Pre-installed packages: matplotlib, numpy, pandas, ipython
+
+### Choosing an image variant
+
+Use the **default image** if you:
+- Only need shell command execution
+- Run JavaScript or TypeScript code
+- Want faster cold starts and smaller image size
+
+Use the **Python image** if you:
+- Execute Python code via [Code Interpreter](/sandbox/api/interpreter/)
+- Need data science packages (numpy, pandas, matplotlib)
+- Require Python-specific functionality
+
 ## Creating a custom image
 
 Create a `Dockerfile` in your project root:
 
 ```dockerfile title="Dockerfile"
-FROM docker.io/cloudflare/sandbox:0.3.3
+# Use Python variant if you need Python packages
+FROM docker.io/cloudflare/sandbox:0.3.3-python
 
 # Install additional Python packages
 RUN pip install --no-cache-dir \
@@ -75,6 +121,7 @@ When you run `wrangler dev` or `wrangler deploy`, Wrangler automatically builds
 Run services automatically when the container starts by creating a custom startup script:
 
 ```dockerfile title="Dockerfile"
+# Choose the appropriate base image for your needs
 FROM docker.io/cloudflare/sandbox:0.3.3
 
 COPY my-app.js /workspace/my-app.js