chore: automate stable npm releases with workflow, guide, and PR template

[mtoub]

This pull request introduces a new workflow for publishing stable releases to npm, along with supporting documentation and templates to standardize the release process. The main changes include adding a GitHub Actions workflow for publishing, a detailed release guide, and a new pull request template to improve consistency and clarity.

Release automation and documentation improvements:

• Added a new GitHub Actions workflow (.github/workflows/publish-stable.yml) to automate publishing stable releases to npm, including version validation, building, running checks, publishing, tagging, and creating GitHub Releases.
• Added a comprehensive release guide (.github/RELEASE_GUIDE.md) with step-by-step instructions for publishing, required setup, semantic versioning examples, and common npm commands.
• Introduced a new pull request template (.github/PULL_REQUEST_TEMPLATE.md) to standardize PR descriptions, change summaries, testing details, and checklists.

[Copilot]

Pull Request Overview

This PR introduces automated stable release publishing capabilities for the @fevertokens/packages npm package through GitHub Actions, along with supporting documentation and a PR template.

• Adds a workflow for publishing stable releases to npm with version validation and automated GitHub release creation
• Provides a release guide documenting the workflow usage and setup requirements
• Includes a comprehensive PR template to standardize contributions

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
.github/workflows/publish-stable.yml	GitHub Actions workflow that automates stable releases with npm publishing, version bumping, and GitHub release creation
.github/RELEASE_GUIDE.md	Documentation covering release workflow usage, npm token setup, and versioning examples
.github/PULL_REQUEST_TEMPLATE.md	Standardized PR template with checklist for change types, testing, and code review requirements

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