ci: increase max-turns from 20 to 30

[YuminosukeSato]

Summary

Increase Claude Code max-turns from 20 to 30 based on actual usage patterns.

Problem

PR #92 used 21 turns and hit the 20-turn limit, causing the review to fail with exit code 1 despite completing successfully.

Evidence from PR #92:

{
  "is_error": false,
  "num_turns": 21,
  "total_cost_usd": 0.36
}

The review was actually successful (is_error: false) but failed because it exceeded max-turns.

Observed Usage Patterns

Recent PRs after rebase:

• PR test: stabilize unix socket test paths #90: 18 turns, $0.51, 58 seconds ✅
• PR test: add pool concurrency coverage #92: 21 turns, $0.36, 111 seconds ❌ (exceeded 20-turn limit)

Changes

- claude_args: "--max-turns 20 --model claude-opus-4-5-20251101"
+ claude_args: "--max-turns 30 --model claude-opus-4-5-20251101"

Cost Analysis

Current (max-turns: 20)

• Average: ~$0.40/PR
• Risk: Incomplete reviews when hitting limit

Proposed (max-turns: 30)

• Expected: $0.40-0.60/PR (based on 20-25 turns)
• Maximum: ~$0.90/PR (if using all 30 turns)
• Benefit: Complete reviews without artificial cutoffs

Why 30?

• 50% buffer: 20 → 30 provides cushion for complex PRs
• Prevents incomplete reviews: Better to complete than hit limit
• Cost-effective: Still reasonable cost per review
• Opus needs time: Thorough analysis requires multiple reasoning steps

Trade-offs

✅ Benefits:

• Complete reviews without hitting limits
• More comprehensive security analysis
• Better architectural insights

❌ Costs:

• Potentially higher API costs per PR (~$0.20 increase)
• Longer review times

Alternative Considered

Keep max-turns at 20 and accept incomplete reviews → Rejected because incomplete reviews defeat the purpose of automated code review.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Increases the Claude Code workflow --max-turns limit to avoid CI failures when reviews exceed the previous 20-turn cap.

Changes:

• Bump claude_args --max-turns from 20 to 30 in the GitHub Actions workflow.

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