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/ar.ts

@@ -1491,7 +1491,9 @@ export const ar: TranslationResources = {
         cursor: "السطر {{line}}، العمود {{column}}",
         preview: "معاينة",
         source: "المصدر",
-        unavailableTitle: "الملف غير متاح على القرص",
+        deletedTitle: "تم حذف الملف من القرص",
+        checkFailedTitle: "تعذّر التحقق من الملف على القرص",
+        preservedDescription: "تم الاحتفاظ بالنسخة المفتوحة.",
         conflictDescription: "تم الاحتفاظ بالمحتوى المحلي. اختر الإصدار الذي تريد إبقاءه.",
         overwrite: "استبدال",
         reload: "إعادة تحميل",