Add Trash/Shares/Recent tabs, file sharing, Details sheet, and rebrand to Noo

Major additions since the initial rebuild:
- New tabs: Trash, Shares, Recent, configurable tab visibility/order/default
- Nextcloud sharing: search users/teams, internal link, email shares,
  public links, "others with access" - in its own Share bottom sheet
- Details bottom sheet (Info/Versions/Activity) with a persistent peek
  panel in the media viewer, reachable from selection, swipe, and the
  media viewer
- Files/Photos: tap-and-hold multi-select with a sticky selection toolbar,
  swipe actions (favorite/delete/share), sticky sort/filter controls,
  list/grid views, breadcrumb chips, whole-account Photos view
- Media viewer: pinch/double-tap zoom on images, predictive-back support,
  fixed PDF zoom-out floor
- Settings: Material You theming incl. AMOLED black, configurable bottom
  bar tabs, swipe actions, media seek bar style, and folder-listing cache
  policy (never/periodic/manual) to cut down on refetching
- Login flow moved to an in-app Chrome Custom Tab with retry-tolerant
  polling
- Replaced ad hoc widgets with native Material 3 equivalents (toggle
  IconButtons, SliverAppBar selection toolbar, SearchBar, drag handles)
- Rebrand: app renamed to Noo throughout, package id -> dev.ayushya.noo,
  new adaptive launcher icon

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

lib/widgets/app_tab_view_builder.dart

@@ -0,0 +1,28 @@
+import 'package:flutter/material.dart';
+import '../models/app_tab.dart';
+import '../views/activity_view.dart';
+import '../views/files_view.dart';
+import '../views/photos_view.dart';
+import '../views/recent_view.dart';
+import '../views/shares_view.dart';
+import '../views/trash_view.dart';
+
+/// Builds the view widget for a given [AppTab]. Shared by the main shell
+/// (for visible tabs) and the "more tabs" dropdown (for launching a tab
+/// that's currently hidden from the bottom nav bar).
+Widget buildAppTabView(AppTab tab, ScrollController controller) {
+  switch (tab) {
+    case AppTab.files:
+      return FilesView(scrollController: controller);
+    case AppTab.photos:
+      return PhotosView(scrollController: controller);
+    case AppTab.activity:
+      return ActivityView(scrollController: controller);
+    case AppTab.trash:
+      return TrashView(scrollController: controller);
+    case AppTab.shares:
+      return SharesView(scrollController: controller);
+    case AppTab.recent:
+      return RecentView(scrollController: controller);
+  }
+}