[Documentation] feat comprehensive CONTRIBUTING.md and Demo movie for open-source development

[Yoo-SH]

Summary of Changes

Added comprehensive CONTRIBUTING.md guide to establish clear development workflow and contribution standards for the open-source project. This document provides detailed guidelines for Git workflow, pull request process, code review standards, and commit message conventions to help new contributors understand the project structure and maintain code quality.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Test addition

Related Issues

This addresses the need for clear contribution guidelines to improve open-source project accessibility and maintainability.

Testing Instructions

1. Navigate to the repository root directory
2. Open the CONTRIBUTING.md file
3. Verify all sections are properly formatted and readable
4. Check that all links and code examples are correctly displayed
5. Ensure the document follows markdown best practices

Screenshots (if applicable)

N/A - Documentation only change

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

This CONTRIBUTING.md establishes:

• Git Flow based branching strategy with clear naming conventions
• Comprehensive PR guidelines with detailed templates
• Code review standards and completion criteria
• Commit message conventions following conventional commits
• Step-by-step workflows for features, hotfixes, and releases

The guide will help standardize the development process and make it easier for new contributors to participate in the project effectively.

[Copilot]

Pull Request Overview

This PR adds comprehensive contribution guidelines and documentation to improve the open-source development experience. The changes establish clear standards for Git workflow, pull requests, code reviews, and commit conventions to help new contributors participate effectively.

• Adds detailed CONTRIBUTING.md with Git Flow branching strategy and development workflows
• Includes PR templates and code review guidelines with specific checklists
• Establishes commit message conventions following conventional commits format
• Adds a demo video link to the README.md

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
CONTRIBUTING.md	Complete contribution guide with branching strategy, PR guidelines, code review standards, and commit conventions
README.md	Adds demo video section with embedded link

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_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The demo link URLs are inconsistent. The image source ends with '...92a' while the link destination ends with '...92ae'. This will cause the clickable demo link to point to a different resource than the displayed image.

Suggested change

	[](https://github.com/user-attachments/assets/55482003-4bb8-4316-bea7-200ecf5bf92ae)
	[](https://github.com/user-attachments/assets/55482003-4bb8-4316-bea7-200ecf5bf92a)

[Copilot]

The documentation mentions both 'main' and 'master' branch names, which could create confusion. Consider standardizing on one branch naming convention (typically 'main' for modern repositories) throughout the document.

Suggested change

	- **`main`** (or `master`): Production-ready code
	- **`main`**: Production-ready code