connection settings cleanup and mock test added. removed bluetooth implementation

app/lib/ui/widgets/battery_indicator_bar.dart

@@ -26,8 +26,12 @@ import '../dmc_colors.dart';
 class BatteryIndicatorBar extends StatelessWidget {
   const BatteryIndicatorBar({super.key, required this.percent});
 
-  /// 0-100, ungeklemmter Rohwert aus TelemetryFrame.batteryPercent.
-  final int percent;
+  /// 0-100, ungeklemmter Rohwert aus TelemetryFrame.batteryPercent - null,
+  /// solange noch kein Telemetrie-Frame vorliegt (Verbindungsaufbau laeuft
+  /// noch). Rendert dann einen neutralen "keine Daten"-Zustand statt eines
+  /// Balkens bei 0%, das faelschlich als kritischer Ladestand gelesen werden
+  /// koennte (siehe MissionFooterBar.showBattery).
+  final int? percent;
 
   /// Absolute Positionen (vom linken Rand aus), an denen rot in orange und
   /// orange in gruen uebergeht - siehe Klassendoku.
@@ -51,7 +55,46 @@ class BatteryIndicatorBar extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final clampedPercent = percent.clamp(0, 100);
+    final rawPercent = percent;
+    if (rawPercent == null) {
+      return SizedBox(
+        height: _pillHeight,
+        width: double.infinity,
+        child: Stack(
+          clipBehavior: Clip.none,
+          children: [
+            Positioned(
+              left: 0,
+              right: 0,
+              top: (_pillHeight - _barHeight) / 2,
+              height: _barHeight,
+              child: ColoredBox(color: Colors.white.withValues(alpha: _trackAlpha)),
+            ),
+            Center(
+              child: Container(
+                height: _pillHeight,
+                constraints: const BoxConstraints(minWidth: _pillMinWidth),
+                padding: const EdgeInsets.symmetric(horizontal: 6),
+                alignment: Alignment.center,
+                decoration: BoxDecoration(
+                  color: Colors.black.withValues(alpha: _pillNeutralAlpha),
+                  borderRadius: BorderRadius.circular(_pillHeight / 2),
+                ),
+                child: const Text(
+                  '--%',
+                  style: TextStyle(
+                    color: Colors.white70,
+                    fontSize: 11,
+                    fontWeight: FontWeight.w600,
+                  ),
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+    }
+    final clampedPercent = rawPercent.clamp(0, 100);
 
     return SizedBox(
       height: _pillHeight,