feat: redesign bench calibration (factor/offset), add Ttank/P2 displays, fix sensor calibration

- Replace P1-P6 rational transfer function with factor/offset model for bench params
- Add explicit rx/tx direction flags in bench XML configuration
- Add T.Tank (BenchTemp) and P2 (AnalogSensor2) to temperature/pressure display
- Apply SensorConfiguration calibration to pressure channels, fix empty sensors.xml fallback
- Add live value labels to flowmeter charts
- Hide pump live values and PSG encoder standalone label
- Add K-Line connection state model, improve KWP service and status displays
- Restructure .claude/skills into subdirectory format

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Views/UserControls/FlowmeterChartView.xaml

@@ -9,8 +9,13 @@
             <RowDefinition Height="*"/>
         </Grid.RowDefinitions>
 
-        <TextBlock Text="{Binding Title}" FontSize="11" FontWeight="SemiBold"
-                   Foreground="DimGray" Margin="4,0"/>
+        <StackPanel Orientation="Horizontal" Margin="4,0">
+            <TextBlock Text="{Binding Title}" FontSize="11" FontWeight="SemiBold"
+                       Foreground="DimGray"/>
+            <TextBlock Text="{Binding CurrentValue, StringFormat=F3}" FontSize="14" FontWeight="Bold"
+                       Foreground="#4080FF" FontFamily="Consolas" Margin="8,0,0,0"
+                       VerticalAlignment="Center"/>
+        </StackPanel>
 
         <lvc:CartesianChart Grid.Row="1" Height="120"
                             Series="{Binding Series}"