Fix broken links in homepage

[bhouston]

Description

Fixed broken links in the homepage that were causing build failures.

Changes Made

• Updated the "Get Started" button link from /docs/index to /docs
• Updated the "Usage Guide" link from /docs/usage/index to /docs/usage

Root Cause

The homepage was using incorrect URL patterns that didn't match the Docusaurus configuration. The links were pointing to /docs/index and /docs/usage/index instead of the correct paths /docs and /docs/usage.

Verification

The build now completes successfully without any broken link errors.