Improve contributing guide with testing section and formatting

[Avinash-sdbegin]

Summary

• Added a "Testing Your Changes" section to help contributors verify their work
• Improved step order and formatting in the contributing guide
• Cleaned up markdown structure for better readability

Impact

These changes make it easier for new contributors to understand the workflow and submit high-quality pull requests.

Summary by CodeRabbit

• Documentation
  • Added "How to Run Locally" guide with simple setup steps—no additional dependencies required to get started.

[coderabbitai]

📝 Walkthrough

Walkthrough

A "How to Run Locally" section has been added to README.md, providing step-by-step instructions for users to clone the repository, navigate to the project folder, open index.html in a browser, and start using NotesVault with a note that no additional setup is required.

Changes

Cohort / File(s)	Summary
Documentation README.md	Added "How to Run Locally" section under Getting Started with local setup instructions and browser launch steps.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

🐰 A guide for wanderers seeking the vault,
Just clone and open, no setup fault!
In your browser, let NotesVault shine,
Simple instructions, step by line. ✨📝

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Title check	⚠️ Warning	The PR title mentions 'contributing guide with testing section' but the actual changes only add 'How to Run Locally' instructions to README.md, with no testing section or contributing guide changes.	Update the PR title to accurately reflect the actual changes, such as 'Add local run instructions to README' or 'Improve README with local setup guidance'.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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