Rename --configuration to --size for clarity

The option `--size` is much more intuitive than `--configuration` when
the values are small/medium/large.

Changes:
- CLI option renamed from `--configuration` to `--size`
- API still receives `configuration` parameter (internal mapping)
- Updated all documentation to use `--size`
- Updated examples in README, docs, and quickstart

Users now use:
- `cua create --os linux --size small --region north-america`

Instead of:
- `cua create --os linux --configuration small --region north-america`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/content/docs/get-started/quickstart.mdx

@@ -61,13 +61,13 @@ You can run your Cua computer in the cloud (recommended for easiest setup), loca
     3. Create a cloud sandbox:
     ```bash
     # Linux sandbox (recommended)
-    cua create --os linux --configuration small --region north-america
+    cua create --os linux --size small --region north-america
 
     # Or Windows sandbox
-    cua create --os windows --configuration small --region north-america
+    cua create --os windows --size small --region north-america
 
     # Or macOS sandbox
-    cua create --os macos --configuration small --region north-america
+    cua create --os macos --size small --region north-america
     ```
 
     4. Note your sandbox name and password from the output
@@ -472,10 +472,10 @@ Create a cloud sandbox where your AI agents will run:
 
 ```bash
 # Create a Linux sandbox (recommended for most use cases)
-cua create --os linux --configuration small --region north-america
+cua create --os linux --size small --region north-america
 
 # Or create a Windows sandbox
-cua create --os windows --configuration small --region north-america
+cua create --os windows --size small --region north-america
 
 ```
 

docs/content/docs/libraries/cua-cli/commands.mdx

@@ -17,7 +17,7 @@ The CLI supports **two command styles** for flexibility:
 **Flat style** (quick & concise):
 ```bash
 cua list
-cua create --os linux --configuration small --region north-america
+cua create --os linux --size small --region north-america
 cua start my-sandbox
 ```
 
@@ -129,24 +129,24 @@ test-windows      stopped   another-pass-456   test-windows.containers.cloud.try
 Create a new sandbox.
 
 ```bash
-cua create --os <OS> --configuration <SIZE> --region <REGION>
+cua create --os <OS> --size <SIZE> --region <REGION>
 ```
 
 **Required Options:**
 - `--os` - Operating system: `linux`, `windows`, `macos`
-- `--configuration` - Sandbox size: `small`, `medium`, `large`
+- `--size` - Sandbox size: `small`, `medium`, `large`
 - `--region` - Region: `north-america`, `europe`, `asia-pacific`, `south-america`
 
 **Examples:**
 ```bash
 # Create a small Linux sandbox in North America
-cua create --os linux --configuration small --region north-america
+cua create --os linux --size small --region north-america
 
 # Create a medium Windows sandbox in Europe
-cua create --os windows --configuration medium --region europe
+cua create --os windows --size medium --region europe
 
 # Create a large macOS sandbox in Asia Pacific
-cua create --os macos --configuration large --region asia-pacific
+cua create --os macos --size large --region asia-pacific
 ```
 
 **Response Types:**

docs/content/docs/libraries/cua-cli/index.mdx

@@ -25,7 +25,7 @@ curl -LsSf https://cua.ai/cli/install.sh | sh
 cua login
 
 # Create a new Linux sandbox
-cua create --os linux --configuration small --region north-america
+cua create --os linux --size small --region north-america
 
 # List your sandboxes
 cua list