🧱 Realtime call infra

lib/widgets/chat/call_overlay.dart

@@ -0,0 +1,53 @@
+import 'package:auto_route/auto_route.dart';
+import 'package:flutter/material.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:island/pods/call.dart';
+import 'package:island/route.gr.dart';
+
+/// A floating bar that appears when user is in a call but not on the call screen.
+class CallOverlayBar extends HookConsumerWidget {
+  final String roomId;
+  const CallOverlayBar({super.key, required this.roomId});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final callState = ref.watch(callNotifierProvider);
+    // Only show if connected and not on the call screen
+    if (!callState.isConnected) return const SizedBox.shrink();
+
+    return Positioned(
+      left: 16,
+      right: 16,
+      bottom: 32,
+      child: GestureDetector(
+        onTap: () {
+          context.router.push(CallRoute(roomId: roomId));
+        },
+        child: Material(
+          elevation: 8,
+          borderRadius: BorderRadius.circular(24),
+          color: Theme.of(context).colorScheme.primary,
+          child: Container(
+            padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 12),
+            child: Row(
+              mainAxisAlignment: MainAxisAlignment.spaceBetween,
+              children: [
+                Row(
+                  children: [
+                    Icon(Icons.call, color: Colors.white),
+                    const SizedBox(width: 12),
+                    const Text(
+                      'In call',
+                      style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold, fontSize: 16),
+                    ),
+                  ],
+                ),
+                const Icon(Icons.arrow_forward_ios, color: Colors.white, size: 18),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}