Build an AI PR Reviewer with GitHub Actions

# .github/workflows/ai-review.yml
name: AI Code Review
on:
  pull_request:
    types: [opened, synchronize]

jobs:
  review:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      
      - name: Get diff
        id: diff
        run: |
          DIFF=$(git diff origin/main...HEAD -- '*.ts' '*.tsx' '*.py' '*.js')
          echo "diff<<EOF" >> $GITHUB_OUTPUT
          echo "$DIFF" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT
      
      - name: AI Review
        uses: actions/github-script@v7
        env:
          IZZI_API_KEY: ${{ secrets.IZZI_API_KEY }}
        with:
          script: |
            const diff = `${{ steps.diff.outputs.diff }}`;
            if (!diff.trim()) return;
            
            const response = await fetch('https://api.izziapi.com/v1/chat/completions', {
              method: 'POST',
              headers: {
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${process.env.IZZI_API_KEY}`,
              },
              body: JSON.stringify({
                model: 'claude-sonnet-4-20250514',
                messages: [{
                  role: 'user',
                  content: `Review this PR diff. Focus on:
1. Security vulnerabilities (critical)
2. Bugs and logic errors (high)
3. Performance issues (medium)
4. Code style improvements (low)

Format: bullet list with severity and file:line.

${diff.substring(0, 15000)}`
                }],
                max_tokens: 2000,
              }),
            });
            
            const data = await response.json();
            const review = data.choices[0].message.content;
            
            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.name,
              issue_number: context.issue.number,
              body: `## 🤖 AI Code Review\n\n${review}\n\n---\n*Powered by Izzi API + Claude Sonnet 4*`,
            });