ci: cancel previous workflow runs on new push

[vreshch]

Summary

This PR adds concurrency control to our GitHub Actions workflows to automatically cancel previous in-progress runs when new commits are pushed.

Changes

• Added concurrency configuration to deploy.yml workflow
• Added concurrency configuration to pr-validation.yml workflow

Benefits

• Prevents multiple CI runs from executing simultaneously on the same branch/PR
• Saves CI resources and reduces execution time
• Only the latest run will continue, previous ones are automatically canceled

How it works

• deploy.yml: Groups by branch reference (deploy-${{ github.ref }})
• pr-validation.yml: Groups by PR number or branch reference (pr-validation-${{ github.event.pull_request.number || github.ref }})
• Both have cancel-in-progress: true to cancel older runs when a new one starts

[github-actions]

✅ Pull Request Validation Successful

Step Results:

• ✅ 📦 Install dependencies: true
• ✅ 🔍 Run linting: true
• ✅ 🧪 Run tests: true
• ✅ 🏗️ Build packages: true

🎉 All quality checks passed! Ready to merge.

📋 View workflow run

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🐳 Docker Images Built Successfully!

🏷️ Tag: pr-16

• Backend: ✅ Built
• Frontend: ✅ Built

📋 View workflow

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⏰ Generated at: 2025-12-12T01:31:38.848Z