Files view: the update row's change link is "Show diff" (v2.6.5)

- an update row whose image changed (or whose bytes were first observed)
  offered a generic "Details" link; it now says "Show diff" — Russian
  «Изменения» — while a card-side change keeps its "Changed on card!" link
  (both open the same change modal)
- the now-unused 'Details' RU key is gone; tests update the wiring pin and
  the Russian-translation list; 527 Python + 61 Node tests
- README/README_RUS mention the new label; PWA_VERSION/pyproject/version.py
  2.6.5, SW cache simtrace-analyser-v79

frontend/index.html

@@ -2234,7 +2234,7 @@ async function renderFileView() {
     }
     view.innerHTML = timeline.map(op => {
         const diff = op.change_ref
-            ? `<button class="file-op-diff" data-diff="${escapeHtml(op.change_ref.file)}|${op.change_ref.idx}" title="${t('Show the change')}">${op.kind === 'card_change' ? t('Changed on card!') : t('Details')}</button>`
+            ? `<button class="file-op-diff" data-diff="${escapeHtml(op.change_ref.file)}|${op.change_ref.idx}" title="${t('Show the change')}">${op.kind === 'card_change' ? t('Changed on card!') : t('Show diff')}</button>`
             : '';
         return `<div class="file-op ${fileOpClass(op.kind)}" data-idx="${op.index}">
             <span>${escapeHtml(fileOpLabel(op))}</span>${diff}
@@ -3226,7 +3226,7 @@ function onFilterChange() {
 }
 
 // ──────────────────── Versioning ────────────────────
-const PWA_VERSION = '2.6.4';
+const PWA_VERSION = '2.6.5';
 const MIN_SERVER_VERSION = '2.3.0';
 
 function parseVersion(v) {
@@ -3273,8 +3273,8 @@ const LANG_RU = {
     'Read': 'Чтение',
     'Update': 'Запись',
     'Changed on card!': 'Изменено на карте!',
+    'Show diff': 'Изменения',
     'Change details': 'Подробности изменения',
-    'Details': 'Подробнее',
     'changed': 'изменено',
     'newly observed': 'впервые наблюдается',
     'never observed': 'не наблюдалось',