ci: add conventional commit check for PR titles

[shikhar]

Summary

• Adds a CI job using amannn/action-semantic-pull-request to validate PR titles follow conventional commit format
• Only runs on pull_request events
• Ensures PR titles produce valid conventional commits on squash merge, which release-plz relies on for changelog generation

Test plan

• Verify this PR's own title passes the check
• Open a PR with a non-conventional title and verify it fails

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

Adds automated validation for PR titles to enforce conventional commit format, ensuring proper changelog generation with release-plz on squash merges.

• Adds conventional-commit job using amannn/action-semantic-pull-request@v5
• Only runs on pull request events with proper conditional check
• Adds required pull-requests: read permission to workflow
• Aligns with existing project style guide requirement (line 21 in CLAUDE.md)

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• Simple CI configuration addition that adds automation for an existing project convention, uses a well-established GitHub Action with appropriate permissions, and has proper conditional logic
• No files require special attention

Important Files Changed

Filename	Overview
.github/workflows/ci.yml	Adds conventional commit check job using amannn/action-semantic-pull-request@v5 with proper permissions

_{Last reviewed commit: 9863282}