change cli init across docs (#1245)

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

* **Documentation**
* Updated installation and setup instructions across all documentation,
README files, and getting started guides to use the new Stack CLI
command format for project initialization. Users will now see the
updated command throughout documentation and framework-specific setup
guides.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

docs/code-examples/setup.ts

@@ -6,7 +6,7 @@ export const setupExamples = {
       {
         language: 'JavaScript',
         framework: 'Next.js',
-        code: `npx @stackframe/init-stack@latest`,
+        code: `npx @stackframe/stack-cli@latest init`,
         highlightLanguage: 'bash',
         filename: 'Terminal'
       }