Add support for downloading media

Fixes #85

lib/widgets/file_card.dart

@@ -1,4 +1,6 @@
+import "package:flutter_riverpod/flutter_riverpod.dart";
 import "package:material_ui/material_ui.dart";
+import "package:nexus/helpers/extensions/save_attachment.dart";
 import "package:nexus/helpers/extensions/size_to_string.dart";
 import "package:nexus/models/info/file.dart";
 
@@ -6,10 +8,11 @@ final class const FileCard(
   final Uri uri,
   final FileInfo? info, {
   final String? filename,
+  final bool encrypted = false,
   super.key,
-}) extends StatelessWidget {
+}) extends ConsumerWidget {
   @override
-  Widget build(BuildContext context) => SizedBox(
+  Widget build(BuildContext context, WidgetRef ref) => SizedBox(
     width: 320,
     child: Card(
       color: Theme.of(context).colorScheme.surfaceContainer,
@@ -17,8 +20,15 @@ final class const FileCard(
         leading: Icon(Icons.file_copy),
         title: Text(filename ?? "file", maxLines: 1, overflow: .ellipsis),
         subtitle: info?.size == null ? null : Text(info!.size!.sizeAsString),
-        // TODO: Downloading files
-        trailing: IconButton(onPressed: null, icon: Icon(Icons.download)),
+        trailing: IconButton(
+          onPressed: () => context.saveAttachment(
+            ref,
+            uri,
+            encrypted: encrypted,
+            filename: filename,
+          ),
+          icon: Icon(Icons.download),
+        ),
       ),
     ),
   );