Rebuild UI on the Noo design system

Replaces the Material 3 screens with the Noo design system: warm
neutrals, one violet accent, pill controls, Schibsted Grotesk/
Instrument Sans, Lucide icons, no gradients/shadows.

- New lib/widgets/noo/ component kit (core, lists, files, media, nav,
  overlays) plus lib/theme/design_tokens.dart for the color/type/space/
  radius/motion tokens.
- Rebuilt the app shell (top/bottom bars, drawer, desktop sidebar and
  toolbar), every tab (Files/Offline, Photos, Favorites, Recent,
  Activity, Trash, Shares), Settings, the lock and login screens, the
  media viewer, search, the details/share sheets, and the share-upload
  and move/copy destination pickers.
- Added a design canvas (linked from DESIGN_SYSTEM.md) covering the
  screens the spec didn't already describe, with matching Android and
  iOS chrome; wrote up the approved recipes into DESIGN_SYSTEM.md §4.
- Removed now-dead legacy widgets (media_grid_tile, swipeable_item,
  sync_status_badge, selectable_thumbnail) and updated
  architecture.md/styling.md/standards.md to describe the new
  structure and component/testing conventions.
- Added widget tests for the noo/ component kit.

This is a UI-only rework: no provider/model/service behavior changed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lib/widgets/app_drawer.dart

@@ -0,0 +1,83 @@
+import 'package:flutter/material.dart';
+import 'package:lucide_icons_flutter/lucide_icons.dart';
+import 'package:provider/provider.dart';
+import '../models/app_tab.dart';
+import '../providers/files_controller.dart';
+import '../providers/session_controller.dart';
+import '../providers/settings_controller.dart';
+import '../providers/trash_controller.dart';
+import 'noo/core/noo_avatar.dart';
+import 'noo/nav/noo_drawer.dart';
+import 'shell/shell_common.dart';
+
+/// The mobile drawer (DESIGN_SYSTEM.md 2 "Drawer" / 3; `drawer` in
+/// `Mobile Screen.dc.html`): account block, storage bar, the tabs not
+/// pinned to the bottom nav bar ("More"), Settings, and an "Edit tabs"
+/// link. Opened the same way as before (menu icon in [AppTopBar]), but
+/// built on [NooDrawer] instead of the old Material [Drawer] + ad hoc rows.
+///
+/// Tapping a "More" tab switches the shell straight to it (rather than
+/// pushing it as a standalone screen, like the pre-rework `MoreTabsButton`
+/// did) via `SettingsController.requestTab` - the same one-shot mechanism
+/// `SearchView`/`FavoritesView`/`ShareUploadView` already use to jump the
+/// shell to a tab from outside it, so `MainShellView` needs no extra
+/// plumbing to support it.
+class AppDrawer extends StatelessWidget {
+  const AppDrawer({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final session = context.watch<SessionController>();
+    final settings = context.watch<SettingsController>();
+    final quota = context.watch<FilesController>().quota;
+    // Cheap and already loaded when the Trash tab has been visited this
+    // session - not worth a fetch just to populate a drawer badge.
+    final trashCount = context.watch<TrashController>().items.length;
+    final hiddenTabs = settings.tabOrder
+        .where((t) => settings.hiddenTabs.contains(t))
+        .toList();
+
+    void closeAndOpenSettings() {
+      Navigator.pop(context);
+      openSettings(context);
+    }
+
+    return NooDrawer(
+      account: NooDrawerAccount(
+        avatar: NooAvatar(
+          initials: accountInitial(session.username),
+          current: true,
+          size: 48,
+        ),
+        name: session.username,
+        subtitle: serverHost(session.serverUrl),
+        onTap: closeAndOpenSettings,
+        onSwitchAccount: () => showAccountSwitcher(context),
+      ),
+      storage: NooDrawerStorage(
+        value: quotaFraction(quota),
+        label: quotaUsedLabel(quota),
+      ),
+      moreItems: [
+        for (final tab in hiddenTabs)
+          NooDrawerItem(
+            icon: tab.icon,
+            label: tab.label,
+            count: tab == AppTab.trash && trashCount > 0
+                ? '$trashCount'
+                : null,
+            onTap: () {
+              Navigator.pop(context);
+              settings.requestTab(tab);
+            },
+          ),
+      ],
+      settings: NooDrawerItem(
+        icon: LucideIcons.settings,
+        label: 'Settings',
+        onTap: closeAndOpenSettings,
+      ),
+      footer: NooDrawerLink(onTap: closeAndOpenSettings),
+    );
+  }
+}