fix(appbar): prevent title overflow on narrow widths (#205)

Use width-aware layout in AppBarTitle to avoid RenderFlex overflows under tight title constraints and larger text scaling. Hide subtitle and signal indicators progressively when space is limited while preserving normal behavior on wider layouts.

lib/widgets/app_bar.dart

@@ -14,35 +14,54 @@ class AppBarTitle extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final connector = context.watch<MeshCoreConnector>();
+    final selfName = connector.selfName;
 
-    return Row(
-      mainAxisAlignment: MainAxisAlignment.start,
-      children: [
-        leading ?? const SizedBox.shrink(),
-        Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          mainAxisSize: MainAxisSize.min,
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        final availableWidth = constraints.hasBoundedWidth
+            ? constraints.maxWidth
+            : MediaQuery.sizeOf(context).width;
+        final compact = availableWidth < 240;
+        final showSubtitle =
+            !compact && connector.isConnected && selfName != null;
+        final showBattery = availableWidth >= 60;
+        final showSnr = availableWidth >= 110;
+        final showIndicators = showBattery || showSnr;
+
+        return Row(
+          mainAxisAlignment: MainAxisAlignment.start,
           children: [
-            Text(title, overflow: TextOverflow.ellipsis),
-            if (connector.isConnected && connector.selfName != null)
-              Text(
-                '(${connector.selfName})',
-                style: TextStyle(fontSize: 14, color: Colors.grey[600]),
-                overflow: TextOverflow.ellipsis,
+            leading ?? const SizedBox.shrink(),
+            Expanded(
+              child: Column(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  Text(title, maxLines: 1, overflow: TextOverflow.ellipsis),
+                  if (showSubtitle)
+                    Text(
+                      '($selfName)',
+                      style: TextStyle(fontSize: 14, color: Colors.grey[600]),
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
+                    ),
+                ],
               ),
+            ),
+            if (showIndicators) const SizedBox(width: 6),
+            if (showIndicators)
+              Row(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  if (showBattery) BatteryIndicator(connector: connector),
+                  if (showSnr) SNRIndicator(connector: connector),
+                ],
+              ),
+            trailing ?? const SizedBox.shrink(),
           ],
-        ),
-        const SizedBox(width: 8),
-        Row(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          mainAxisSize: MainAxisSize.min,
-          children: [
-            BatteryIndicator(connector: connector),
-            SNRIndicator(connector: connector),
-          ],
-        ),
-        trailing ?? const SizedBox.shrink(),
-      ],
+        );
+      },
     );
   }
 }