[good first issue] Improve README.md formatting and readability

[Cima9642]

📝 Description

The README could use some formatting polish! This is a great low-risk task for
someone comfortable with Markdown.

✅ Suggested improvements (pick one or more)

• Add a Table of Contents at the top with anchor links
• Make sure all code blocks use proper syntax highlighting (```bash)
• Ensure consistent heading levels throughout the document
• Add a blank line between sections for better spacing

🏷️ Labels

good first issue · documentation · enhancement

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🎨 Markdown formatting reference: https://www.markdownguide.org/basic-syntax/
Comment below if you plan to work on this so we don't get duplicate PRs!