Add connection dialog for Android host/port configuration

Android app now shows a connection dialog on launch where the user
enters the MCP server hostname and port. On Connect, the main view
is loaded with the specified server URL. Added ConnectionViewModel
in Core and ConnectionDialogView in the Android project.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sharpninja

src/RequestTracker.Android/App.axaml.cs

@@ -1,4 +1,5 @@
 using Avalonia;
+using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Data.Core.Plugins;
 using Avalonia.Markup.Xaml;
@@ -25,12 +26,28 @@ public override void OnFrameworkInitializationCompleted()
 
             try
             {
-                var clipboardService = new AndroidClipboardService();
-                var vm = new MainWindowViewModel(clipboardService);
-                singleView.MainView = DeviceFormFactor.IsTablet()
-                    ? new TabletMainView { DataContext = vm }
-                    : (Avalonia.Controls.Control)new PhoneMainView { DataContext = vm };
-                vm.InitializeAfterWindowShown();
+                var connectionVm = new ConnectionViewModel();
+                var connectionView = new ConnectionDialogView { DataContext = connectionVm };
+                singleView.MainView = connectionView;
+
+                connectionVm.Connected += mcpBaseUrl =>
+                {
+                    try
+                    {
+                        var clipboardService = new AndroidClipboardService();
+                        var vm = new MainWindowViewModel(clipboardService, mcpBaseUrl);
+                        singleView.MainView = DeviceFormFactor.IsTablet()
+                            ? new TabletMainView { DataContext = vm }
+                            : (Control)new PhoneMainView { DataContext = vm };
+                        vm.InitializeAfterWindowShown();
+                    }
+                    catch (Exception ex)
+                    {
+                        Console.Error.WriteLine($"Connection failed: {ex}");
+                        connectionVm.ErrorMessage = $"Connection failed: {ex.Message}";
+                        connectionVm.IsConnecting = false;
+                    }
+                };
             }
             catch (Exception ex)
             {

src/RequestTracker.Android/Views/ConnectionDialogView.axaml

@@ -0,0 +1,67 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:vm="using:RequestTracker.Core.ViewModels"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d" d:DesignWidth="400" d:DesignHeight="600"
+             x:Class="RequestTracker.Android.Views.ConnectionDialogView"
+             x:DataType="vm:ConnectionViewModel">
+
+    <Grid VerticalAlignment="Center" HorizontalAlignment="Center"
+          MaxWidth="360" Margin="24">
+        <Border Background="{DynamicResource SystemControlBackgroundChromeMediumLowBrush}"
+                CornerRadius="12" Padding="28" BoxShadow="0 4 16 0 #40000000">
+            <StackPanel Spacing="16">
+                <!-- Title -->
+                <TextBlock Text="Connect to Server"
+                           FontSize="22" FontWeight="SemiBold"
+                           HorizontalAlignment="Center" Margin="0,0,0,8"/>
+
+                <TextBlock Text="Enter the hostname and port of the MCP session log server."
+                           TextWrapping="Wrap" FontSize="13" Foreground="Gray"
+                           HorizontalAlignment="Center" TextAlignment="Center"
+                           Margin="0,0,0,4"/>
+
+                <!-- Host -->
+                <StackPanel Spacing="4">
+                    <TextBlock Text="Host" FontSize="13" FontWeight="Medium"/>
+                    <TextBox Text="{Binding Host}"
+                             Watermark="e.g. 192.168.1.100"
+                             FontSize="16" Padding="10,8"
+                             IsEnabled="{Binding !IsConnecting}"/>
+                </StackPanel>
+
+                <!-- Port -->
+                <StackPanel Spacing="4">
+                    <TextBlock Text="Port" FontSize="13" FontWeight="Medium"/>
+                    <TextBox Text="{Binding Port}"
+                             Watermark="e.g. 5000"
+                             FontSize="16" Padding="10,8"
+                             IsEnabled="{Binding !IsConnecting}"/>
+                </StackPanel>
+
+                <!-- Error -->
+                <TextBlock Text="{Binding ErrorMessage}"
+                           Foreground="Red" FontSize="13"
+                           TextWrapping="Wrap"
+                           IsVisible="{Binding ErrorMessage, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+
+                <!-- Connect Button -->
+                <Button Content="Connect"
+                        Command="{Binding ConnectCommand}"
+                        HorizontalAlignment="Stretch"
+                        HorizontalContentAlignment="Center"
+                        FontSize="16" FontWeight="SemiBold"
+                        Padding="0,12"
+                        IsEnabled="{Binding !IsConnecting}"
+                        Margin="0,8,0,0"/>
+
+                <!-- Connecting indicator -->
+                <TextBlock Text="Connecting..."
+                           FontSize="13" Foreground="Gray"
+                           HorizontalAlignment="Center"
+                           IsVisible="{Binding IsConnecting}"/>
+            </StackPanel>
+        </Border>
+    </Grid>
+</UserControl>

src/RequestTracker.Android/Views/ConnectionDialogView.axaml.cs

@@ -0,0 +1,12 @@
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace RequestTracker.Android.Views;
+
+public partial class ConnectionDialogView : UserControl
+{
+    public ConnectionDialogView()
+    {
+        InitializeComponent();
+    }
+}

src/RequestTracker.Core/ViewModels/ConnectionViewModel.cs

@@ -0,0 +1,51 @@
+using System;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace RequestTracker.Core.ViewModels;
+
+public partial class ConnectionViewModel : ViewModelBase
+{
+    [ObservableProperty]
+    private string _host = "192.168.1.100";
+
+    [ObservableProperty]
+    private string _port = "5000";
+
+    [ObservableProperty]
+    private string _errorMessage = "";
+
+    [ObservableProperty]
+    private bool _isConnecting;
+
+    /// <summary>Raised when the user taps Connect with a valid URL.</summary>
+    public event Action<string>? Connected;
+
+    [RelayCommand]
+    private void Connect()
+    {
+        ErrorMessage = "";
+
+        if (string.IsNullOrWhiteSpace(Host))
+        {
+            ErrorMessage = "Host is required.";
+            return;
+        }
+
+        if (string.IsNullOrWhiteSpace(Port) || !int.TryParse(Port.Trim(), out var portNumber) || portNumber < 1 || portNumber > 65535)
+        {
+            ErrorMessage = "Port must be between 1 and 65535.";
+            return;
+        }
+
+        var url = $"http://{Host.Trim()}:{portNumber}";
+        if (!Uri.TryCreate(url, UriKind.Absolute, out _))
+        {
+            ErrorMessage = "Invalid host or port.";
+            return;
+        }
+
+        IsConnecting = true;
+        Connected?.Invoke(url);
+    }
+}

src/RequestTracker.Core/ViewModels/MainWindowViewModel.cs

@@ -207,6 +207,12 @@ public MainWindowViewModel(IClipboardService clipboardService)
         _mcpSessionService = new McpSessionLogService(GetMcpBaseUrl());
     }
 
+    public MainWindowViewModel(IClipboardService clipboardService, string mcpBaseUrl)
+    {
+        _clipboardService = clipboardService;
+        _mcpSessionService = new McpSessionLogService(mcpBaseUrl);
+    }
+
     /// <summary>Command for tree item tap (handles directory expand/collapse and MCP node refresh).</summary>
     [RelayCommand]
     private void TreeItemTapped(FileNode? node)