add: [project-sequencer-statemachine] ErasePitchStateを追加

[sigprogramming]

内容

ErasePitchStateの追加とIdleStateの変更を行います。

関連 Issue

• ソング：シーケンサーのプレビュー処理をステートパターンで実装して置き換える #2403

その他

[voicevox-preview-pages]

🚀 プレビュー用ページを作成しました 🚀

• 📝 エディタ
• 📖 Storybook

更新時点でのコミットハッシュ：d90a48c

Copilot reviewed 1 out of 1 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (8)

src/sing/stateMachine/sequencerStateMachine.ts:1178

• The error message 'innerContext is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.previewErasePitch: innerContext is undefined.'

throw new Error("innerContext is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1181

• The error message 'previewPitchEdit.value is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.previewErasePitch: previewPitchEdit.value is undefined.'

throw new Error("previewPitchEdit.value is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1184

• The error message 'previewPitchEdit.value.type is not erase.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.previewErasePitch: previewPitchEdit.value.type is not erase.'

throw new Error("previewPitchEdit.value.type is not erase.");

src/sing/stateMachine/sequencerStateMachine.ts:1215

• The error message 'innerContext is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.onEnter: innerContext is undefined.'

throw new Error("innerContext is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1241

• The error message 'innerContext is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.process: innerContext is undefined.'

throw new Error("innerContext is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1258

• The error message 'innerContext is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.onExit: innerContext is undefined.'

throw new Error("innerContext is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1261

• The error message 'previewPitchEdit is undefined.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.onExit: previewPitchEdit is undefined.'

throw new Error("previewPitchEdit is undefined.");

src/sing/stateMachine/sequencerStateMachine.ts:1264

• The error message 'previewPitchEdit.type is not erase.' could be more descriptive. Consider including the method name for better context, e.g., 'ErasePitchState.onExit: previewPitchEdit.type is not erase.'

throw new Error("previewPitchEdit.type is not erase.");

[Hiroshiba]

ほぼLGTMです！！

[Hiroshiba]

LGTM！！

もしかしてそろそろステートマシン完成が近い感じですかね･･･！！
楽しみ！！