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/widgets/device_code_dialog.dart

@@ -1,16 +1,10 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:material_symbols_icons/symbols.dart';
-import 'package:url_launcher/url_launcher.dart';
 
-import '../focus/focusable_button.dart';
-import '../focus/focusable_wrapper.dart';
 import '../i18n/strings.g.dart';
 import '../models/trackers/device_code.dart';
 import '../utils/snackbar_helper.dart';
-import 'app_icon.dart';
-import 'dialog_action_button.dart';
-import 'loading_indicator_box.dart';
+import 'pending_auth_dialog.dart';
 
 /// Shared device-code activation dialog for Trakt and Simkl (RFC 8628).
 ///
@@ -25,11 +19,6 @@ class DeviceCodeDialog extends StatelessWidget {
 
   const DeviceCodeDialog({super.key, required this.code, required this.serviceName, required this.onCancel});
 
-  Future<void> _open() async {
-    final url = code.verificationUrlComplete ?? code.verificationUrl;
-    await launchUrl(Uri.parse(url), mode: LaunchMode.externalApplication);
-  }
-
   Future<void> _copy(BuildContext context) async {
     await Clipboard.setData(ClipboardData(text: code.userCode));
     if (!context.mounted) return;
@@ -39,70 +28,31 @@ class DeviceCodeDialog extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
-    return AlertDialog(
-      title: Text(t.services.deviceCode.title(service: serviceName)),
-      content: Column(
-        mainAxisSize: .min,
-        crossAxisAlignment: .start,
-        children: [
-          Text(t.services.deviceCode.body(url: code.verificationUrl), style: theme.textTheme.bodyMedium),
-          const SizedBox(height: 16),
-          Center(
-            child: FocusableWrapper(
-              onSelect: () => _copy(context),
-              semanticLabel: t.services.deviceCode.copyCode,
-              descendantsAreFocusable: false,
-              useBackgroundFocus: true,
-              borderRadius: 8,
-              child: InkWell(
-                canRequestFocus: false,
-                onTap: () => _copy(context),
-                borderRadius: BorderRadius.circular(8),
-                child: Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
-                  child: Text(
-                    code.userCode,
-                    style: theme.textTheme.displaySmall?.copyWith(
-                      fontFeatures: const [FontFeature.tabularFigures()],
-                      letterSpacing: 4,
-                      fontWeight: .w600,
-                    ),
-                  ),
+    return PendingAuthDialog(
+      title: t.services.deviceCode.title(service: serviceName),
+      body: t.services.deviceCode.body(url: code.verificationUrl),
+      url: code.verificationUrlComplete ?? code.verificationUrl,
+      openLabel: t.services.deviceCode.openToActivate(service: serviceName),
+      onCancel: onCancel,
+      children: [
+        Center(
+          child: CopyTapRegion(
+            onCopy: () => _copy(context),
+            semanticLabel: t.services.deviceCode.copyCode,
+            child: Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
+              child: Text(
+                code.userCode,
+                style: theme.textTheme.displaySmall?.copyWith(
+                  fontFeatures: const [FontFeature.tabularFigures()],
+                  letterSpacing: 4,
+                  fontWeight: .w600,
                 ),
               ),
             ),
           ),
-          const SizedBox(height: 16),
-          SizedBox(
-            width: double.infinity,
-            child: FocusableButton(
-              onPressed: _open,
-              useBackgroundFocus: true,
-              child: FilledButton.icon(
-                icon: const AppIcon(Symbols.open_in_new_rounded),
-                label: Text(t.services.deviceCode.openToActivate(service: serviceName)),
-                onPressed: _open,
-              ),
-            ),
-          ),
-          const SizedBox(height: 16),
-          Row(
-            children: [
-              const LoadingIndicatorBox(size: 16),
-              const SizedBox(width: 12),
-              Expanded(child: Text(t.services.deviceCode.waitingForAuthorization, style: theme.textTheme.bodySmall)),
-            ],
-          ),
-        ],
-      ),
-      actions: [
-        DialogActionButton(
-          onPressed: () {
-            onCancel();
-            Navigator.of(context).pop();
-          },
-          label: t.common.cancel,
         ),
+        const SizedBox(height: 16),
       ],
     );
   }