Clarify changed and deleted files in the file viewer (#2670)

* fix(app): distinguish changed and deleted files

Successful reads now reconcile transient missing events without letting stale
cached data mask a deletion. File notices expose only actions valid for the
current buffer state.

* fix(app): preserve file state ordering

* fix(app): allow retrying file checks

* fix(app): clear unchanged file conflicts

* fix(app): keep file conflict recovery consistent

Own disk observation and read ordering in one model so stale reads and failed subscriptions cannot produce contradictory actions.

* fix(app): allow retrying file preview errors

Preserve daemon read errors and expose retry for initial and non-editable file loads.

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

@@ -1507,7 +1507,9 @@ export const ja: TranslationResources = {
         cursor: "{{line}} 行、{{column}} 列",
         preview: "プレビュー",
         source: "ソース",
-        unavailableTitle: "ディスク上のファイルを利用できません",
+        deletedTitle: "ファイルはディスク上から削除されました",
+        checkFailedTitle: "ディスク上のファイルを確認できませんでした",
+        preservedDescription: "開いているコピーは保持されています。",
         conflictDescription: "ローカルの内容は保持されています。残すバージョンを選択してください。",
         overwrite: "上書き",
         reload: "再読み込み",