chore: Prismaマイグレーションテーブルを削除

[KinjiKawaguchi]

Summary

• Prismaからの移行は完了済みのため、不要になった _prisma_migrations テーブルのスキーマ定義とデータを削除
• Drizzleマイグレーション（DROP TABLE "_prisma_migrations" CASCADE）を生成

Test plan

• npm run typecheck が通ること
• npm run lint が通ること
• npm run db:generate で差分が出ないこと
• マイグレーション適用後に _prisma_migrations テーブルが削除されていること

🤖 Generated with Claude Code

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[devin-ai-integration]

Devin Review found 1 potential issue.

[devin-ai-integration]

📝 Info: CASCADE on DROP TABLE is safe but worth noting

The migration at drizzle/0004_loose_wasp.sql:1 uses DROP TABLE "_prisma_migrations" CASCADE. The CASCADE keyword will also drop any objects that depend on this table (e.g., views, foreign keys referencing it). Since _prisma_migrations is an internal Prisma bookkeeping table with no foreign key references from other tables (confirmed by inspecting the snapshot), CASCADE has no practical effect here beyond a simple DROP TABLE. It's not a bug, but in general, using CASCADE on production drops warrants a second look to ensure nothing unexpected is removed.

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[Copilot]

Pull request overview

Prisma 移行完了後に残っていた _prisma_migrations テーブルを、Drizzle 側のスキーマ定義およびマイグレーションで削除して、DBスキーマ管理を Drizzle に一本化するPRです。

Changes:

• Drizzle の schema.ts から _prisma_migrations テーブル定義を削除
• Drizzle マイグレーション 0004 で _prisma_migrations を DROP
• Drizzle の meta（snapshot / journal）を更新

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/infrastructure/drizzle/schema.ts	_prisma_migrations のテーブル定義を削除し、現行スキーマ定義から切り離し
drizzle/0004_loose_wasp.sql	_prisma_migrations テーブル削除を行うマイグレーションを追加
drizzle/meta/0004_snapshot.json	_prisma_migrations 削除後のスナップショットを追加
drizzle/meta/_journal.json	新規マイグレーション 0004_loose_wasp をジャーナルに追加

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[Copilot]

DROP TABLE "_prisma_migrations" CASCADE is more destructive than necessary here and can silently drop dependent objects (views, FKs, etc.) if they exist. Consider using DROP TABLE IF EXISTS "_prisma_migrations" (without CASCADE) so the migration is idempotent and fails loudly if something unexpectedly depends on the table.

Suggested change

	DROP TABLE "_prisma_migrations" CASCADE;
	DROP TABLE IF EXISTS "_prisma_migrations";