refactor: share search field, auth dialog, and list-download plumbing

The search screens, the out-of-band auth dialogs, the live TV guide and the
list-download paths each carried their own copy of the same shell. Extracts
SearchInputField and PendingAuthDialog and routes the duplicated download
and guide helpers through one implementation.

lib/utils/download_utils.dart

@@ -148,14 +148,7 @@ Future<DownloadResult?> showDownloadOptionsAndQueue(
     }
 
     if (filter == DownloadFilter.unwatched && kind == MediaKind.show && context.mounted) {
-      final syncChoice = await showOptionPickerDialog<_SyncChoice>(
-        context,
-        title: t.downloads.downloadNow,
-        options: [
-          (icon: Symbols.download_rounded, label: t.downloads.downloadOnce, value: _SyncChoice.downloadOnce),
-          (icon: Symbols.sync_rounded, label: t.downloads.keepSynced, value: _SyncChoice.keepSynced),
-        ],
-      );
+      final syncChoice = await _showSyncChoiceDialog(context);
       if (syncChoice == null || !context.mounted) return null;
       keepSynced = syncChoice == _SyncChoice.keepSynced;
     }
@@ -226,22 +219,12 @@ Future<DownloadResult?> showListDownloadOptionsAndQueue(
   final selectedFilter = await showOptionPickerDialog<DownloadFilter>(
     context,
     title: t.downloads.downloadNow,
-    options: [
-      (icon: Symbols.download_rounded, label: t.downloads.allEpisodes, value: DownloadFilter.all),
-      (icon: Symbols.visibility_off_rounded, label: t.downloads.unwatchedOnly, value: DownloadFilter.unwatched),
-    ],
+    options: _filterOptions(DownloadFilter.all, DownloadFilter.unwatched),
   );
 
   if (selectedFilter == null || !context.mounted) return null;
 
-  final syncChoice = await showOptionPickerDialog<_SyncChoice>(
-    context,
-    title: t.downloads.downloadNow,
-    options: [
-      (icon: Symbols.download_rounded, label: t.downloads.downloadOnce, value: _SyncChoice.downloadOnce),
-      (icon: Symbols.sync_rounded, label: t.downloads.keepSynced, value: _SyncChoice.keepSynced),
-    ],
-  );
+  final syncChoice = await _showSyncChoiceDialog(context);
   if (syncChoice == null || !context.mounted) return null;
 
   final serverId = rootMetadata.serverId ?? client.serverId;
@@ -279,36 +262,21 @@ Future<DownloadResult?> showListDownloadOptionsAndQueue(
   );
 }
 
-/// Shows the shared list-download dialog for a playlist.
-Future<DownloadResult?> showPlaylistDownloadOptionsAndQueue(
-  BuildContext context, {
-  required MediaItem playlistMetadata,
-  required List<MediaItem> items,
-  required MediaServerClient client,
-  required DownloadProvider downloadProvider,
-}) => showListDownloadOptionsAndQueue(
-  context,
-  rootMetadata: playlistMetadata,
-  targetType: ContentTypes.playlist,
-  items: items,
-  client: client,
-  downloadProvider: downloadProvider,
-);
+/// The all/unwatched option rows, shared by the pickers that differ only in
+/// how they spell those two values.
+List<({IconData? icon, String label, T value})> _filterOptions<T>(T all, T unwatched) => [
+  (icon: Symbols.download_rounded, label: t.downloads.allEpisodes, value: all),
+  (icon: Symbols.visibility_off_rounded, label: t.downloads.unwatchedOnly, value: unwatched),
+];
 
-/// Shows the shared list-download dialog for a collection.
-Future<DownloadResult?> showCollectionDownloadOptionsAndQueue(
-  BuildContext context, {
-  required MediaItem collectionMetadata,
-  required List<MediaItem> items,
-  required MediaServerClient client,
-  required DownloadProvider downloadProvider,
-}) => showListDownloadOptionsAndQueue(
+/// Asks whether to download once or keep the target synced.
+Future<_SyncChoice?> _showSyncChoiceDialog(BuildContext context) => showOptionPickerDialog<_SyncChoice>(
   context,
-  rootMetadata: collectionMetadata,
-  targetType: ContentTypes.collection,
-  items: items,
-  client: client,
-  downloadProvider: downloadProvider,
+  title: t.downloads.downloadNow,
+  options: [
+    (icon: Symbols.download_rounded, label: t.downloads.downloadOnce, value: _SyncChoice.downloadOnce),
+    (icon: Symbols.sync_rounded, label: t.downloads.keepSynced, value: _SyncChoice.keepSynced),
+  ],
 );
 
 Future<int?> _showEpisodeCountDialog(
@@ -375,10 +343,7 @@ Future<bool> editSyncRuleFilter(
   final selected = await showOptionPickerDialog<String>(
     context,
     title: t.downloads.editSyncFilter,
-    options: [
-      (icon: Symbols.download_rounded, label: t.downloads.allEpisodes, value: SyncRuleFilter.all),
-      (icon: Symbols.visibility_off_rounded, label: t.downloads.unwatchedOnly, value: SyncRuleFilter.unwatched),
-    ],
+    options: _filterOptions(SyncRuleFilter.all, SyncRuleFilter.unwatched),
   );
   if (selected == null || selected == currentFilter || !context.mounted) return false;
 

lib/utils/live_tv_grouping.dart

@@ -45,15 +45,15 @@ List<LiveTvChannelGroup> groupLiveTvChannelsBySource(List<LiveTvChannel> channel
 }
 
 String liveTvChannelSourceKey(LiveTvChannel channel) {
-  final serverId = _nonEmpty(channel.serverId) ?? '';
-  final providerSource = _nonEmpty(channel.favoriteSource) ?? _nonEmpty(channel.lineup) ?? '';
-  final dvrSource = _nonEmpty(channel.liveDvrKey) ?? '';
+  final serverId = liveTvNonEmpty(channel.serverId) ?? '';
+  final providerSource = liveTvNonEmpty(channel.favoriteSource) ?? liveTvNonEmpty(channel.lineup) ?? '';
+  final dvrSource = liveTvNonEmpty(channel.liveDvrKey) ?? '';
   return '$serverId\u0000$providerSource\u0000$dvrSource';
 }
 
 String liveTvChannelSourceLabel(LiveTvChannel channel) {
-  final serverLabel = _nonEmpty(channel.serverName) ?? _nonEmpty(channel.serverId) ?? 'Live TV';
-  final sourceTitle = _nonEmpty(channel.liveTvSourceTitle);
+  final serverLabel = liveTvNonEmpty(channel.serverName) ?? liveTvNonEmpty(channel.serverId) ?? 'Live TV';
+  final sourceTitle = liveTvNonEmpty(channel.liveTvSourceTitle);
   if (sourceTitle == null || sourceTitle == serverLabel) return serverLabel;
   return '$serverLabel - $sourceTitle';
 }
@@ -62,8 +62,8 @@ String _deduplicatedLabel(LiveTvChannelGroup group) {
   if (group.channels.isEmpty) return group.label;
   final first = group.channels.first;
   final suffixes = [
-    _nonEmpty(first.liveTvSourceTitle),
-    _nonEmpty(first.liveDvrKey),
+    liveTvNonEmpty(first.liveTvSourceTitle),
+    liveTvNonEmpty(first.liveDvrKey),
     liveTvProviderIdentifierForChannel(first),
   ];
   String? suffix;
@@ -76,8 +76,3 @@ String _deduplicatedLabel(LiveTvChannelGroup group) {
   if (suffix == null || group.label.contains(suffix)) return group.label;
   return '${group.label} - $suffix';
 }
-
-String? _nonEmpty(String? value) {
-  final trimmed = value?.trim();
-  return trimmed == null || trimmed.isEmpty ? null : trimmed;
-}

lib/utils/live_tv_matching.dart

@@ -2,14 +2,14 @@ import '../models/livetv_channel.dart';
 import '../models/livetv_program.dart';
 
 bool liveTvProgramMatchesChannel(LiveTvProgram program, LiveTvChannel channel) {
-  final programChannel = _nonEmpty(program.channelIdentifier);
+  final programChannel = liveTvNonEmpty(program.channelIdentifier);
   if (programChannel == null) return false;
   if (programChannel != channel.key && programChannel != channel.identifier) return false;
 
   if (!_nullableIdsMatch(program.serverId, channel.serverId)) return false;
   if (!_nullableIdsMatch(program.liveDvrKey, channel.liveDvrKey)) return false;
 
-  final programProvider = _nonEmpty(program.providerIdentifier);
+  final programProvider = liveTvNonEmpty(program.providerIdentifier);
   final channelProvider = liveTvProviderIdentifierForChannel(channel);
   if (programProvider != null && channelProvider != null && programProvider != channelProvider) return false;
 
@@ -17,26 +17,27 @@ bool liveTvProgramMatchesChannel(LiveTvProgram program, LiveTvChannel channel) {
 }
 
 String? liveTvProviderIdentifierForChannel(LiveTvChannel channel) {
-  final source = _nonEmpty(channel.favoriteSource);
+  final source = liveTvNonEmpty(channel.favoriteSource);
   if (source != null) {
     final uri = Uri.tryParse(source);
-    if (uri != null && uri.pathSegments.isNotEmpty) return _nonEmpty(uri.pathSegments.last);
+    if (uri != null && uri.pathSegments.isNotEmpty) return liveTvNonEmpty(uri.pathSegments.last);
 
     final slashIndex = source.lastIndexOf('/');
     if (slashIndex >= 0 && slashIndex < source.length - 1) {
-      return _nonEmpty(source.substring(slashIndex + 1));
+      return liveTvNonEmpty(source.substring(slashIndex + 1));
     }
   }
-  return _nonEmpty(channel.lineup);
+  return liveTvNonEmpty(channel.lineup);
 }
 
 bool _nullableIdsMatch(String? a, String? b) {
-  final left = _nonEmpty(a);
-  final right = _nonEmpty(b);
+  final left = liveTvNonEmpty(a);
+  final right = liveTvNonEmpty(b);
   return left == null || right == null || left == right;
 }
 
-String? _nonEmpty(String? value) {
+/// Trimmed [value], or null when it is null, empty, or whitespace-only.
+String? liveTvNonEmpty(String? value) {
   final trimmed = value?.trim();
   return trimmed == null || trimmed.isEmpty ? null : trimmed;
 }