[WORKFLOW] Create PR template validation workflow #717

Create GitHub Actions workflow that validates PR template compliance.

Details

• File: .github/workflows/validate-pr-template.yml
• Runs on: pull_request (opened, synchronize, edited)
• Detects branch prefix (feat/, fix/, chore/, etc.)
• Checks if PR body contains required template sections
• Fails if wrong template detected
• Auto-comments with helpful correction link

Validation Logic

1. Extract branch name from PR
2. Look up expected template from PULL_REQUEST_TEMPLATE/config.yml
3. Check PR body for required sections (changelog, risk assessment, test steps, etc.)
4. If missing sections: post comment with template link
5. If very wrong template: add "needs-template-fix" label
6. Block merge if template missing (status check)

Required Sections by Type

• All PRs: Linked issues, Changelog
• feat/: Changelog (Added), Test steps, Accessibility checklist
• fix/: Root cause, Verification, Risk assessment
• chore/: Changelog (if user-facing), Test steps
• docs/: Changelog (optional), no code changes

Acceptance Criteria

• Workflow created and tested
• Validates template sections correctly
• Auto-comments on template violations
• Blocks merge if critical sections missing
• Works with all branch types

Metadata

Issue Type: Task
Priority: High
Phase: 3 - Automation & Enforcement
Effort: 2h
Depends on: #2, #4

Project: Template Enforcement & Governance