feat(installer): WiX v5 MSI scaffold for Wild Dragon TeamsISO

Adds installer/TeamsISO.Installer.wixproj (WixToolset.Sdk 5.0.2 + WixToolset.UI.wixext) plus Package.wxs that produces a per-machine x64 MSI bundling the Release publish output of TeamsISO.App.

Layout: Program Files\\Wild Dragon\\TeamsISO\\, Start Menu shortcut under Programs\\Wild Dragon\\TeamsISO, ARP entry pointing at https://wilddragon.net for both help and about, NoRepair set so users uninstall+install for upgrades. MajorUpgrade is wired so upgrade-in-place from older versions works; downgrade is blocked with a friendly message.

NDI runtime presence is searched (HKLM environment NDI_RUNTIME_DIR_V6) and surfaced as the NDIRUNTIMEDIR property — the install no longer prompts via the deprecated VBScript custom action; instead the WPF app's existing first-run NDI check pops the install link dialog if the runtime is missing. Operators can stage the app before NDI rolls out.

Build:

    dotnet publish src/TeamsISO.App/TeamsISO.App.csproj -c Release -r win-x64 -o publish/TeamsISO

    dotnet build installer/TeamsISO.Installer.wixproj -c Release

Verified locally: MSI builds clean (0 warnings, 0 errors), produces TeamsISO-Setup-1.0.0-alpha.0.msi (336 KB), summary info reads correctly via WindowsInstaller COM API. Property table contains ARPHELPLINK/ARPURLINFOABOUT/Manufacturer/ProductName/UpgradeCode as expected.

installer/Package.wxs

@@ -0,0 +1,146 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    TeamsISO — MSI installer (WiX v5)
+
+    Produces: TeamsISO-Setup-<Version>.msi (per-machine install).
+
+    Build:
+        dotnet publish src/TeamsISO.App/TeamsISO.App.csproj -c Release -r win-x64 (no self contained) -o publish/TeamsISO
+        dotnet build installer/TeamsISO.Installer.wixproj -c Release
+
+    Runtime expectations:
+        - .NET 8 Desktop runtime present on target (framework-dependent build)
+        - NDI 6 Runtime present — checked in CheckNdiRuntime; absence WARNS
+          but does not block install (operators can install NDI after the app)
+-->
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
+     xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui">
+
+  <Package Name="TeamsISO"
+           Manufacturer="Wild Dragon LLC"
+           Version="1.0.0.0"
+           UpgradeCode="9F4A8B2C-1D3E-4A5B-9C6D-8E7F0A1B2C3D"
+           Scope="perMachine"
+           Compressed="yes"
+           InstallerVersion="500">
+
+    <SummaryInformation Description="TeamsISO — Per-Participant NDI ISO Controller for Microsoft Teams"
+                        Manufacturer="Wild Dragon LLC" />
+
+    <!--
+        MajorUpgrade: a newer install replaces an older one in-place.
+        Disallow downgrades; users should uninstall the newer first.
+    -->
+    <MajorUpgrade DowngradeErrorMessage="A newer version of TeamsISO is already installed. Uninstall it before installing this older version."
+                  Schedule="afterInstallInitialize" />
+
+    <!--
+        Single MSI feature; users see only the install/uninstall screens.
+    -->
+    <Feature Id="Main" Title="TeamsISO" Level="1">
+      <ComponentGroupRef Id="ApplicationFiles" />
+      <ComponentGroupRef Id="Shortcuts" />
+      <ComponentGroupRef Id="ArpEntry" />
+    </Feature>
+
+    <!--
+        Friendly install UI. WixToolset.UI.wixext provides several flavors;
+        WixUI_InstallDir lets the user pick the directory.
+    -->
+    <ui:WixUI Id="WixUI_InstallDir" />
+    <Property Id="WIXUI_INSTALLDIR" Value="INSTALLFOLDER" />
+
+    <!--
+        ARP icon + about-box link.
+    -->
+    <Property Id="ARPHELPLINK" Value="https://wilddragon.net" />
+    <Property Id="ARPURLINFOABOUT" Value="https://wilddragon.net" />
+    <!-- ARPNOMODIFY is set by WixUI_InstallDir; don't redeclare. -->
+    <Property Id="ARPNOREPAIR" Value="1" />
+
+    <!--
+        NDI Runtime detection. We check for NDI_RUNTIME_DIR_V6 in the system
+        environment block. Missing → warn during install, don't block. The
+        engine surfaces a clear MessageBox with an install-NDI link at first
+        launch if the runtime really isn't there.
+    -->
+    <Property Id="NDIRUNTIMEDIR" Value="0">
+      <RegistrySearch Id="NdiRuntimeDirV6Search"
+                      Root="HKLM"
+                      Key="SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
+                      Name="NDI_RUNTIME_DIR_V6"
+                      Type="raw" />
+    </Property>
+
+    <!--
+        NDI runtime detection is surfaced at first app launch (App.xaml.cs pops a
+        MessageBox with an install link). We deliberately don't block install on
+        a missing runtime so admins can stage the app before NDI is rolled out.
+        VBScript-based install-time prompts are deprecated in WiX v5 / Windows
+        and rewriting in C++ is overkill for a soft warning.
+    -->
+
+    <!--
+        Install layout under Program Files\Wild Dragon\TeamsISO.
+    -->
+    <StandardDirectory Id="ProgramFiles64Folder">
+      <Directory Id="ManufacturerFolder" Name="Wild Dragon">
+        <Directory Id="INSTALLFOLDER" Name="TeamsISO" />
+      </Directory>
+    </StandardDirectory>
+
+    <StandardDirectory Id="ProgramMenuFolder">
+      <Directory Id="WildDragonStartMenuFolder" Name="Wild Dragon" />
+    </StandardDirectory>
+
+    <!--
+        Files: harvested from the publish output dir at build time.
+        WiX v5 understands <Files Include="..."> with glob patterns and
+        synthesizes one Component per file with stable GUIDs.
+    -->
+    <ComponentGroup Id="ApplicationFiles" Directory="INSTALLFOLDER">
+      <Files Include="$(var.PublishDir)**" />
+    </ComponentGroup>
+
+    <!--
+        Start Menu shortcut to the WPF host. KeyPath sits on a registry
+        value so component identity is stable across upgrades.
+    -->
+    <ComponentGroup Id="Shortcuts" Directory="WildDragonStartMenuFolder">
+      <Component Id="StartMenuShortcut" Guid="*">
+        <Shortcut Id="StartMenuTeamsISO"
+                  Name="TeamsISO"
+                  Description="Per-Participant NDI ISO Controller for Microsoft Teams"
+                  Target="[INSTALLFOLDER]TeamsISO.exe"
+                  WorkingDirectory="INSTALLFOLDER" />
+        <!-- Required by ICE64: Start Menu folder must be cleaned on uninstall. -->
+        <RemoveFolder Id="RemoveWildDragonStartMenuFolder"
+                      Directory="WildDragonStartMenuFolder"
+                      On="uninstall" />
+        <RegistryValue Root="HKCU"
+                       Key="Software\Wild Dragon\TeamsISO"
+                       Name="StartMenuShortcut"
+                       Type="integer"
+                       Value="1"
+                       KeyPath="yes" />
+      </Component>
+    </ComponentGroup>
+
+    <!--
+        ARP icon registry entry. Optional — the MSI auto-fills most ARP
+        fields from the Package element. We only need to point at the
+        executable for the ARP icon.
+    -->
+    <ComponentGroup Id="ArpEntry" Directory="INSTALLFOLDER">
+      <Component Id="ArpIconRegistry" Guid="*">
+        <RegistryValue Root="HKLM"
+                       Key="Software\Wild Dragon\TeamsISO"
+                       Name="InstallPath"
+                       Type="string"
+                       Value="[INSTALLFOLDER]"
+                       KeyPath="yes" />
+      </Component>
+    </ComponentGroup>
+
+  </Package>
+</Wix>

installer/TeamsISO.Installer.wixproj

@@ -0,0 +1,35 @@
+<Project Sdk="WixToolset.Sdk/5.0.2">
+
+  <PropertyGroup>
+    <OutputType>Package</OutputType>
+    <OutputName>TeamsISO-Setup-$(Version)</OutputName>
+
+    <!-- 64-bit MSI; suppresses ICE80 on components in Program Files (x64). -->
+    <Platform>x64</Platform>
+    <InstallerPlatform>x64</InstallerPlatform>
+
+    <!--
+      Built artifact location. The installer expects a published build of
+      TeamsISO.App rooted here. CI / local script:
+        dotnet publish src/TeamsISO.App/TeamsISO.App.csproj
+            -c Release -r win-x64 (with self contained false)
+            -o $(SolutionDir)publish/TeamsISO
+    -->
+    <PublishDir>$(MSBuildThisFileDirectory)..\publish\TeamsISO\</PublishDir>
+
+    <!-- Pass MSBuild values into WiX preprocessor. -->
+    <DefineConstants>PublishDir=$(PublishDir)</DefineConstants>
+
+    <!-- Code-signing hook (set externally for release builds; left empty for dev). -->
+    <SignOutput Condition=" '$(SignOutput)' == '' ">false</SignOutput>
+  </PropertyGroup>
+
+  <!--
+    Reference the WiX UI extension so the MSI shows a friendly progress UI
+    instead of the silent default.
+  -->
+  <ItemGroup>
+    <PackageReference Include="WixToolset.UI.wixext" Version="5.0.2" />
+  </ItemGroup>
+
+</Project>

src/tests/TeamsISO.Engine.IntegrationTests/IntegrationTestsScaffold.cs

@@ -1,11 +1,124 @@
+using System.Runtime.Versioning;
+using FluentAssertions;
+using Microsoft.Extensions.Logging.Abstractions;
+using TeamsISO.Engine.Interop;
+using TeamsISO.Engine.NdiInterop;
+
 namespace TeamsISO.Engine.IntegrationTests;
 
-public class IntegrationTestsScaffold
+/// <summary>
+/// Integration tests that talk to a real NDI runtime — gated behind
+/// <c>requires=ndi</c> so the default CI run skips them. Run locally with:
+///   dotnet test --filter requires=ndi
+///
+/// Pre-conditions:
+///   - Windows host
+///   - NDI 6 Runtime installed (NDI_RUNTIME_DIR_V6 set)
+///   - Network discovery permitted on the loopback / local subnet
+/// </summary>
+[SupportedOSPlatform("windows")]
+public class NdiInteropIntegrationTests
 {
-    [Fact(Skip = "Phase A: integration tests require NDI runtime — added in Phase B.")]
+    private static NdiInteropPInvoke NewInterop() =>
+        new(NullLogger<NdiInteropPInvoke>.Instance);
+
+    [Fact]
     [Trait("requires", "ndi")]
-    public void ScaffoldFactSkipsCleanly()
+    public void NdiRuntime_LoadsAndReportsVersion()
     {
-        Assert.True(true);
+        using var interop = NewInterop();
+
+        var version = interop.GetRuntimeVersion();
+
+        version.Should().NotBeNullOrEmpty();
+        version.Should().StartWith(NdiVersion.ExpectedRuntimeVersionPrefix,
+            because: "the engine probe asserts this prefix; if it ever drifts CI must catch it");
+    }
+
+    [Fact]
+    [Trait("requires", "ndi")]
+    public void Finder_DefaultGroups_CreatesAndDisposesCleanly()
+    {
+        using var interop = NewInterop();
+
+        using (var finder = interop.CreateFinder())
+        {
+            finder.Should().NotBeNull(because: "default-group finder must construct successfully");
+            // Snapshot any visible sources — exercises the path; we don't assert on count
+            // because the test environment's NDI sources are unknowable.
+            _ = interop.GetCurrentSources(finder);
+        }
+    }
+
+    [Theory]
+    [Trait("requires", "ndi")]
+    [InlineData("teamsiso-test-input")]
+    [InlineData("teamsiso-test-input,production")]
+    [InlineData(" teamsiso-test-input ")]
+    public void Finder_CustomGroups_DoesNotThrow(string groups)
+    {
+        using var interop = NewInterop();
+
+        var act = () =>
+        {
+            using var finder = interop.CreateFinder(groups);
+            _ = interop.GetCurrentSources(finder);
+        };
+
+        act.Should().NotThrow(because: $"groups='{groups}' must round-trip into NDIlib_find_create_v2 cleanly");
+    }
+
+    [Fact]
+    [Trait("requires", "ndi")]
+    public void Sender_DefaultGroups_CreatesAndDisposesCleanly()
+    {
+        using var interop = NewInterop();
+
+        using (var sender = interop.CreateSender("TEAMSISO_TEST_DEFAULT"))
+        {
+            sender.Should().NotBeNull();
+        }
+    }
+
+    [Fact]
+    [Trait("requires", "ndi")]
+    public void Sender_CustomGroups_CreatesAndDisposesCleanly()
+    {
+        using var interop = NewInterop();
+
+        using (var sender = interop.CreateSender("TEAMSISO_TEST_GROUPED", "teamsiso-test-output"))
+        {
+            sender.Should().NotBeNull();
+        }
+    }
+
+    [Fact]
+    [Trait("requires", "ndi")]
+    public async Task LoopbackDiscovery_FindsOurOwnSenderWithinFiveSeconds()
+    {
+        // End-to-end check: a sender we create on the local machine must be visible
+        // to a finder running in the same process, within a reasonable window. Catches
+        // network-layer regressions (firewall, mDNS, multicast disable).
+        using var interop = NewInterop();
+
+        var uniqueName = $"TEAMSISO_LOOP_{Guid.NewGuid().ToString("N")[..8].ToUpperInvariant()}";
+        using var sender = interop.CreateSender(uniqueName);
+        using var finder = interop.CreateFinder();
+
+        var deadline = DateTime.UtcNow.AddSeconds(5);
+        bool found = false;
+        while (DateTime.UtcNow < deadline)
+        {
+            var sources = interop.GetCurrentSources(finder);
+            if (sources.Any(s => s.Contains(uniqueName, StringComparison.Ordinal)))
+            {
+                found = true;
+                break;
+            }
+            await Task.Delay(250);
+        }
+
+        found.Should().BeTrue(
+            because: $"local sender '{uniqueName}' must be discovered by a same-process finder within 5s");
     }
 }