feat: enable isolated mode by default for better session isolation

- Set browser.isolated = true as default configuration
- Ensures each MCP session gets its own isolated browser context
- Prevents data sharing between different client sessions
- Combined with headed mode for optimal user experience

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

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

src/config.ts

@@ -53,6 +53,7 @@ export type CLIOptions = {
 const defaultConfig: FullConfig = {
   browser: {
     browserName: 'chromium',
+    isolated: true,
     launchOptions: {
       channel: 'chrome',
       headless: false,