feat(toolbox): first-run auto-applies the collected preconfig (no manual walkthrough)

windows/welcome/src/SilverOS.Welcome.UI/Components/Routes.razor

@@ -60,7 +60,7 @@ else
                     <PrefsStep />
                     break;
                 case 4:
-                    <ApplyStep OnComplete="AdvanceToDone" OnRunningChanged="@(v => { _applyRunning = v; StateHasChanged(); })" />
+                    <ApplyStep AutoStart="_autoApply" OnComplete="AdvanceToDone" OnRunningChanged="@(v => { _applyRunning = v; StateHasChanged(); })" />
                     break;
                 case 5:
                     <DoneStep />
@@ -104,6 +104,7 @@ else
     private bool _loading = true;
     private bool _applyRunning = false;
     private bool _toolboxHome = false;
+    private bool _autoApply = false;
     private string? _error;
     private IReadOnlyList<FlavourManifest> _flavours = Array.Empty<FlavourManifest>();
 
@@ -167,6 +168,12 @@ else
 
         if (pre.Bitlocker.Enable && !string.IsNullOrEmpty(pre.Bitlocker.Pin))
             State.BitLockerPin = pre.Bitlocker.Pin;
+
+        // First run with a preconfig: skip the manual walkthrough. Jump straight to the
+        // Apply step and signal it to auto-start (spec §4d: auto-runs once, shows progress
+        // + recovery key, then Done).
+        _currentStep = 4;
+        _autoApply = true;
     }
 
     private void ReRunSetup()

windows/welcome/src/SilverOS.Welcome.UI/Components/Steps/ApplyStep.razor

@@ -50,8 +50,10 @@
 @code {
     [Parameter] public EventCallback OnComplete { get; set; }
     [Parameter] public EventCallback<bool> OnRunningChanged { get; set; }
+    [Parameter] public bool AutoStart { get; set; }
 
     private bool _running;
+    private bool _autoStarted;
     private bool _complete;
     private int _percent;
     private string _stageLabel = "Preparing…";
@@ -71,6 +73,18 @@
             : single[..ErrorDisplayMaxLength] + "…";
     }
 
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        // First-run auto-apply: when the host jumps straight to this step with AutoStart,
+        // kick off the same apply the Start button would, exactly once. The manual path
+        // (AutoStart=false) is untouched.
+        if (firstRender && AutoStart && !_autoStarted)
+        {
+            _autoStarted = true;
+            await StartAsync();
+        }
+    }
+
     public async Task StartAsync()
     {
         // Re-entrancy guard: prevent a second overlapping apply if already running

windows/welcome/tests/SilverOS.Welcome.Tests/ApplyStepTests.cs

@@ -73,6 +73,33 @@ public class ApplyStepTests : TestContext
         Assert.True(completed);
     }
 
+    [Fact]
+    public void AutoStart_triggers_apply_once_without_a_button_click()
+    {
+        var apply = new Mock<IApplyService>();
+        apply.Setup(a => a.RunAsync(It.IsAny<ApplyRequest>(), It.IsAny<IProgress<ApplyProgress>>(), It.IsAny<CancellationToken>()))
+             .Returns(Task.CompletedTask);
+        var state = new WizardState
+        {
+            Flavour = new FlavourManifest { Id = "daily-driver", Hardening = new() { Modules = new[] { "00" } } },
+            BitLockerPin = "123456"
+        };
+        Services.AddSingleton(state);
+        Services.AddSingleton(apply.Object);
+        AddCatalog(Services);
+        AddPreconfig(Services);
+
+        // AutoStart=true should fire StartAsync from OnAfterRenderAsync on first render,
+        // with no Start button click.
+        var cut = RenderComponent<ApplyStep>(p => p.Add(s => s.AutoStart, true));
+
+        cut.WaitForAssertion(() =>
+            apply.Verify(a => a.RunAsync(
+                It.Is<ApplyRequest>(r => r.Flavour.Id == "daily-driver"),
+                It.IsAny<IProgress<ApplyProgress>>(),
+                It.IsAny<CancellationToken>()), Times.Once));
+    }
+
     [Fact]
     public async Task Shows_error_and_retry_button_when_apply_fails()
     {