Polish floating bottom bar: elevation, height, overlap, and FAB shape

- Give the floating bar and search satellite the app's one shadow
  (nooDialogShadow) plus a smaller, tighter height on both platforms.
- Let every tab's scrollable list compute its own bottom clearance
  (bottomBarClearance) instead of a flat 100px, so the floating bar no
  longer overlaps the last row/card.
- Square the Android upload FAB off to a rounded-square radius when the
  bottom bar is attached, keeping it fully round only when floating.
- Let a swipe on a file row trigger its action directly once dragged
  past 1.8x the reveal width, instead of requiring a second tap.

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

lib/widgets/tabs/tab_state_slivers.dart

@@ -1,7 +1,11 @@
 import 'package:flutter/material.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
+import 'package:provider/provider.dart';
+import '../../providers/settings_controller.dart';
 import '../../theme/design_tokens.dart';
 import '../noo/core/noo_button.dart';
+import '../noo/nav/noo_bottom_bar.dart';
+import '../noo/noo_layout.dart';
 
 /// Shared loading/error/empty slivers for Recent/Activity/Trash/Shares (and
 /// any future tab shaped like them: a `CustomScrollView` over one flat
@@ -88,9 +92,29 @@ Widget tabEmptySliver(
   );
 }
 
+/// How much bottom padding a tab's scrollable list needs to clear
+/// [NooBottomBar] and not just butt up against it. [NooBottomBarStyle.
+/// attached] bars aren't drawn behind (no `Scaffold.extendBody`), so
+/// Scaffold already shrinks the body above them - this is then pure
+/// breathing room, not overlap prevention. [NooBottomBarStyle.floating]
+/// bars draw over an extended body instead, so nothing reserves space for
+/// them automatically: the clearance has to cover the bar's own footprint
+/// (see [NooBottomBar.rowHeight]/[NooBottomBar.floatingBottomMargin]) plus
+/// the safe-area inset below it, or the last row ends up hidden under it.
+double bottomBarClearance(BuildContext context) {
+  final settings = context.watch<SettingsController>();
+  if (settings.bottomBarStyle == NooBottomBarStyle.attached) return 100;
+  final barHeight = NooBottomBar.rowHeight(
+    NooLayout.navStyle(context),
+    NooBottomBarStyle.floating,
+  );
+  final safeBottom = MediaQuery.paddingOf(context).bottom;
+  return barHeight + NooBottomBar.floatingBottomMargin + safeBottom + 24;
+}
+
 /// Bottom padding sliver so the last row/card clears the bottom nav/FAB -
 /// same trailing pair every rebuilt tab list ends on.
-const List<Widget> tabBottomInsetSlivers = [
-  SliverToBoxAdapter(child: SizedBox(height: 100)),
-  SliverFillRemaining(hasScrollBody: false, child: SizedBox()),
+List<Widget> tabBottomInsetSlivers(BuildContext context) => [
+  SliverToBoxAdapter(child: SizedBox(height: bottomBarClearance(context))),
+  const SliverFillRemaining(hasScrollBody: false, child: SizedBox()),
 ];