refactor(ui): consolidate file feedback and shared display helpers

lib/utils/local_playback.dart

@@ -1,11 +1,11 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/local_library_provider.dart';
 import 'package:spotiflac_android/providers/playback_provider.dart';
 import 'package:spotiflac_android/utils/file_access.dart';
+import 'package:spotiflac_android/widgets/app_snack_bar.dart';
 
 /// Plays [track] from download history or the local library when a matching
 /// file already exists on disk.
@@ -71,15 +71,7 @@ Future<bool> playLocalIfAvailable(
       return true;
     }
   } catch (e) {
-    if (context.mounted) {
-      ScaffoldMessenger.of(context).showSnackBar(
-        SnackBar(
-          content: Text(
-            context.l10n.snackbarCannotOpenFile(context.friendlyError(e)),
-          ),
-        ),
-      );
-    }
+    if (context.mounted) showCannotOpenFileSnackBar(context, e);
     return true;
   }
 

lib/utils/string_utils.dart

@@ -70,6 +70,22 @@ String formatBytes(int bytes) {
   return '${(bytes / (1024 * 1024 * 1024)).toStringAsFixed(2)} GB';
 }
 
+/// English month abbreviations indexed by `DateTime.month - 1`.
+const List<String> shortMonthNames = [
+  'Jan',
+  'Feb',
+  'Mar',
+  'Apr',
+  'May',
+  'Jun',
+  'Jul',
+  'Aug',
+  'Sep',
+  'Oct',
+  'Nov',
+  'Dec',
+];
+
 /// "m:ss" clock formatting for track durations.
 String formatClock(num seconds) {
   final total = seconds.round();