chore: Add GitHub Actions workflow to automatically close linked issues upon merging pull requests into the dev branch.

[geraldsberongoy]

Auto Close Issue on Dev Merge

Description

This PR adds a GitHub Actions workflow that automatically closes linked issues when a pull request is merged into the dev branch. This automation streamlines our development workflow by reducing manual issue management overhead.

What's New

• Automated Issue Closure: When a PR is merged to dev, any issues referenced with keywords (closes, fixes, resolves, etc.) in the PR description are automatically closed
• Audit Trail: Adds a comment to each closed issue indicating which PR triggered the closure
• Smart Detection: Uses regex pattern matching to find all linked issues in PR descriptions

Technical Details

Workflow Trigger:

• Runs on pull_request events with type closed targeting the dev branch
• Only executes if the PR was actually merged (not just closed)

Permissions:

• issues: write - to close issues and add comments
• pull-requests: read - to read PR body content

Supported Keywords:
The workflow recognizes the following keywords followed by #<issue_number>:

• close, closes, closed
• fix, fixes, fixed
• resolve, resolves, resolved

Example Usage

In your PR description, simply reference issues like:
Closes #15 Fixes #23

Benefits

• ✅ Reduces manual work for maintainers
• ✅ Ensures issues are closed promptly when work is merged
• ✅ Maintains clear traceability between PRs and issues
• ✅ Improves project management workflow

Note: This workflow only affects the dev branch. Issues will be closed when PRs merge to dev, aligning with our development workflow where dev is the primary integration branch.

Closes #15

[marvinjameserosa]

lgtm