feat(video_calls): call ended push, recall button for message

lib/features/video_calls/presentation/widgets/video_call_top_overlay.dart

@@ -9,12 +9,67 @@ abstract final class VideoCallTopOverlay {
       'assets/icons/video_call/poor_connection.svg';
   static const String warningSvg = 'assets/icons/video_call/warning.svg';
 
+  static const double _poorConnectionIconSize = 44;
+  static const double _poorConnectionGlyphSize = 22;
+
+  static OverlayEntry? _poorConnectionEntry;
+
+  static bool get isPoorConnectionIconVisible =>
+      _poorConnectionEntry?.mounted ?? false;
+
   static OverlayState? _resolveOverlayState(BuildContext context) {
     return VideoCallBannerOverlay.overlayState ??
         AppRouter.navigatorKey.currentState?.overlay ??
         Overlay.maybeOf(context, rootOverlay: true);
   }
 
+  /// Compact poor-connection indicator: red square with icon only.
+  static void showPoorConnectionIcon(BuildContext context) {
+    if (isPoorConnectionIconVisible) return;
+
+    hidePoorConnectionIcon();
+
+    final overlayState = _resolveOverlayState(context);
+    late OverlayEntry entry;
+    entry = OverlayEntry(
+      builder: (ctx) {
+        final topInset = MediaQuery.viewPaddingOf(ctx).top;
+        return Positioned(
+          left: 16,
+          top: topInset + 8,
+          width: _poorConnectionIconSize,
+          height: _poorConnectionIconSize,
+          child: Material(
+            color: appTheme.strongRed,
+            borderRadius: BorderRadius.circular(10),
+            elevation: 6,
+            child: Center(
+              child: SvgPicture.asset(
+                poorConnectionSvg,
+                width: _poorConnectionGlyphSize,
+                height: _poorConnectionGlyphSize,
+              ),
+            ),
+          ),
+        );
+      },
+    );
+
+    _poorConnectionEntry = entry;
+    if (overlayState == null) {
+      _poorConnectionEntry = null;
+      return;
+    }
+    overlayState.insert(entry);
+  }
+
+  static void hidePoorConnectionIcon() {
+    final entry = _poorConnectionEntry;
+    _poorConnectionEntry = null;
+    if (entry != null && entry.mounted) {
+      entry.remove();
+    }
+  }
 
   static OverlayEntry insertBanner(
     BuildContext context, {