docs: Make the header consistent and Update the cortex init page

[irfanpena]

Describe Your Changes

• Make the header consistent and Update the cortex init page

Fixes Issues

• Closes https://github.com/janhq/cortex-web/issues/32
• Closes https://github.com/janhq/cortex-web/issues/31

Self Checklist

• [ ] Added relevant comments, esp in complex areas
• [x] Updated docs (for bug fixes / features)
• [ ] Created issues for follow-up changes or refactoring needed

[github-actions[bot]]

Preview URL: https://a9076af4.cortex-docs.pages.dev

[irfanpena]

Comment the OAICoverage component to resolve the error because the API for that still error

[urmauur]

Comment the OAICoverage component to resolve the error because the API for that still error

Fixed the OAICoverage component, the API still has an error, but CI does not block to merge PR @irfanpena