Enhance CLI documentation for browsers create command (#336)

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## TL;DR
Documented the new `kernel browsers create` CLI command.

## Why we made these changes
To provide users with clear instructions and options for the new browser
creation command, improving usability and discoverability.

## What changed?
- `packages/cli/README.md`: Updated to include documentation for the
`kernel browsers create` command, detailing options for persistence,
stealth, and headless modes, along with usage examples.

## Validation
- [ ] Manually reviewed the updated `README.md` for accuracy, clarity,
and completeness of the new command's documentation.
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Author: masnwilliams

README.md

@@ -109,6 +109,10 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 ### Browser Management
 
 - `kernel browsers list` - List running browsers
+- `kernel browsers create` - Create a new browser session
+  - `--persistence-id <id>` - Unique identifier for browser session persistence
+  - `--stealth` - Launch browser in stealth mode to avoid detection
+  - `--headless` - Launch browser without GUI access
 - `kernel browsers delete` - Delete a browser
   - `--by-persistent-id <id>` - Delete by persistent ID
   - `--by-id <id>` - Delete by session ID
@@ -161,6 +165,15 @@ kernel logs my-app --since 1h --with-timestamps
 # List all browsers
 kernel browsers list
 
+# Create a new browser session
+kernel browsers create
+
+# Create a persistent browser session
+kernel browsers create --persistence-id my-browser-session
+
+# Create a headless browser in stealth mode
+kernel browsers create --headless --stealth
+
 # Delete a persistent browser
 kernel browsers delete --by-persistent-id my-browser-session --yes