docs: fix capitalization, punctuation and npm build command in README

[sudhirrathod03]

Small documentation fixes:

• Capitalized sentence beginning for clarity.
• Removed an extra period.
• Corrected npm build to npm run build.

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[sudhirrathod03]

Thank you maintainers!
This is my first open-source PR.
Let me know if any changes are required.

[github-actions]

There hasn't been any activity on this pull request recently, and in order to prioritize active work, it has been marked as stale. This PR will be closed and locked in 7 days if no further activity occurs. Thank you for your contributions!