Update README with branch usage and refactoring info

[tommyming]

Added note about using master branch for bugfixes and ongoing refactoring.

[Copilot]

Pull Request Overview

Update README to communicate branch usage for bug fixes and note ongoing refactoring work

• Add a NOTE callout advising users to use the master branch for latest bug fixes
• Mention ongoing refactoring on a separate branch with forthcoming details

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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

[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

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[tommyming]

@suzuki-0000 sorry seems copilot does not work at all, I may need to request your manual review on this.
(seems updating readme is a hard thing for copilot.)

[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.