feat: photo/video capture-date pipeline + premium UI/UX overhaul

Backend — Photos timeline now groups by real capture date instead of upload time. New MediaMetadataService (FileLifecycleHook) extracts EXIF DateTimeOriginal from images and container creation_time from videos (mov/mp4/mkv) via nom-exif, timezone-correct (OffsetTimeOriginal), persisting captured_at so the existing media_sort_date trigger takes over. Adds POST /admin/photos/metadata/reextract to backfill existing media. Falls back to upload date when no embedded date exists.

Frontend — premium grid cards: combined metadata line (relative date · size, owner avatar when shared), custom selection checkbox with a clear checked state, uniform full-width 4:3 thumbnail tiles independent of filename length, centered file-type icons, and a hit-test fix so checkbox/star/kebab clicks reach the controls (the decorative thumbnail no longer captures pointer events). Notification messages internationalised across all 16 locales. Broader polish: design tokens, a11y/focus-visible states, brand + PWA assets.

Chore — bump semver-compatible dependencies (cargo upgrade); add nom-exif 3.6.1.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

static/js/features/files/wopiEditor.js

@@ -7,6 +7,7 @@
 
 import { loadFiles } from '../../app/filesView.js';
 import { ui } from '../../app/ui.js';
+import { i18n } from '../../core/i18n.js';
 
 class WopiEditor {
     constructor() {
@@ -54,7 +55,7 @@ class WopiEditor {
             window.open(hostUrl, '_blank');
         } catch (error) {
             console.error('Failed to open WOPI editor in tab:', error);
-            ui.showNotification('Could not open the document editor.', 'error');
+            ui.showNotification(i18n.t('notif.errorTitle'), i18n.t('notif.wopiOpenError'));
         }
     }