chore: enable CodeRabbit auto review on draft PRs

[valbeat]

Summary

CodeRabbit の自動レビューがドラフトPRでもスキップされず実行されるようにする。

Changes

• .coderabbit.yaml: reviews.auto_review.drafts を false → true に変更

Notes

• このリポジトリではPRをドラフトで作成する運用のため、drafts: false だと作成直後の自動レビューが常に「Review skipped (Draft detected)」になっていた（例: test: add assertType coverage for untested type inference cases #80）
• ドラフト段階からレビューが不要な場合は、従来どおり @coderabbitai ignore で個別に抑制できる

[gemini-code-assist]

Code Review

This pull request updates the .coderabbit.yaml configuration file to enable automatic reviews for draft pull requests by setting drafts to true under the auto_review section. There are no review comments, and I have no additional feedback to provide.

Important

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (81c6834) to head (6b2c333).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@             Coverage Diff             @@
##                main       #81   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
  Complexity        40        40           
===========================================
  Files              2         2           
  Lines             80        80           
===========================================
  Hits              80        80           

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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[Copilot]

Pull request overview

This PR updates the CodeRabbit configuration so automated reviews run even when a pull request is in Draft state, aligning with the repository’s workflow of creating PRs as drafts.

Changes:

• Enable CodeRabbit auto review on draft PRs by setting reviews.auto_review.drafts: true in .coderabbit.yaml.

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