feat: open Changes as a workspace tab (#2298)

Open the complete working comparison in a desktop workspace tab while preserving inline sidebar diffs when the tab is closed.

Working and commit comparisons share one diff panel, and workspace layout is the sole owner of live tab persistence and identity.

Refs #1520

packages/app/src/i18n/resources/ja.ts

@@ -769,6 +769,8 @@ export const ja: TranslationResources = {
         },
       },
       diff: {
+        openChangesTab: "変更タブを開く",
+        closeChangesTab: "変更タブを閉じる",
         binaryFile: "バイナリファイル",
         tooLarge: "差分が大きすぎて表示できません",
         unified: "ユニファイド差分",
@@ -1510,6 +1512,8 @@ export const ja: TranslationResources = {
       changesLabel: "変更",
       changesSubtitle: "作業ツリーの差分",
       commitSubtitle: "コミット差分",
+      uncommittedSubtitle: "未コミットの変更",
+      baseSubtitle: "{{baseRef}} との比較",
       directoryMissing: "ワークスペースディレクトリが見つかりません。",
       empty: "変更はありません",
       loadError: "差分の読み込みに失敗しました",