feat(apps): AppsStep grouped checkboxes

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -0,0 +1,45 @@
+@using SilverOS.Welcome.Core.Apps
+@inject WizardState State
+
+<div class="step apps-step">
+    <h1>Choose your apps</h1>
+    <p class="step-subtitle">We'll install these during setup. The SilverLABS Stack (browser, VPN, keys) is already included.</p>
+
+    @foreach (var grp in _groups)
+    {
+        <h3 class="apps-group">@GroupTitle(grp.Key)</h3>
+        <div class="apps-grid">
+            @foreach (var app in grp)
+            {
+                <label class="app-card @(State.SelectedApps.Contains(app.Id) ? "selected" : "")">
+                    <input type="checkbox" checked="@State.SelectedApps.Contains(app.Id)"
+                           @onchange="e => Toggle(app.Id, (bool)e.Value!)" />
+                    <span class="app-name">@app.Name</span>
+                    <span class="app-desc">@app.Description</span>
+                </label>
+            }
+        </div>
+    }
+</div>
+
+@code {
+    [Parameter] public IReadOnlyList<AppCatalogEntry> Apps { get; set; } = Array.Empty<AppCatalogEntry>();
+
+    private IEnumerable<IGrouping<string, AppCatalogEntry>> _groups =>
+        Apps.GroupBy(a => a.Group).OrderByDescending(g => g.Key == "essentials");
+
+    private static string GroupTitle(string g) => g switch
+    {
+        "essentials" => "Essentials",
+        "developer" => "Developer tools",
+        "journalist" => "Journalist tools",
+        "daily-driver" => "Everyday apps",
+        "privacy-max" => "Privacy tools",
+        _ => g
+    };
+
+    void Toggle(string id, bool on)
+    {
+        if (on) State.SelectedApps.Add(id); else State.SelectedApps.Remove(id);
+    }
+}