v4.1: two screen-reader fixes — silent start-in-tray, announce on restore

- Starting straight into the tray (StartMinimised / --minimized) no longer plays the "minimise"
  cue; only a genuine user minimise does (the startup path passes playCue:false)
- Restoring the window from the tray now lands focus on a real named control on the active tab so
  NVDA announces it, instead of resting on the role-less QuietTabControl and surfacing silently
- Shared the focus-a-leaf-for-announcement helper between the main window and Preferences

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

src/RemSound.App/AccessibleCheckBox.cs

@@ -27,6 +27,36 @@ internal static class WinEventNotifier
             NotifyWinEvent(EVENT_OBJECT_FOCUS, control.Handle, OBJID_CLIENT, CHILDID_SELF);
         }
     }
+
+    /// <summary>Land NVDA on a named control so a freshly-shown window or dialog announces itself
+    /// instead of surfacing silently. Focuses the first focusable leaf inside <paramref name="page"/>
+    /// (falling back to <paramref name="fallback"/>), forcing a genuine focus CHANGE (ActiveControl=null
+    /// first) and re-firing the MSAA focus event. Used by the Preferences dialog on open and by the
+    /// main window when it's restored from the tray. The page sits inside a <see cref="QuietTabControl"/>
+    /// whose own accessible object is deliberately role-less and nameless, so focusing the tab control
+    /// itself would be silent — this finds a real leaf (the first interactive control on whatever tab
+    /// is showing) instead. Best run deferred (BeginInvoke), after the show/foreground settles.</summary>
+    public static void AnnounceByFocusingLeaf(ContainerControl form, Control? page, Control fallback)
+    {
+        var leaf = FirstFocusableLeaf(page) ?? fallback;
+        form.ActiveControl = null;
+        leaf.Focus();
+        if (leaf.IsHandleCreated) NotifyFocus(leaf);
+    }
+
+    /// <summary>The first visible, enabled, tab-stop control inside <paramref name="container"/>,
+    /// searched depth-first in child order (which matches the order controls were added). Returns a
+    /// real leaf (button / list / combo / checkbox) — never a layout panel or the role-less tab strip.</summary>
+    private static Control? FirstFocusableLeaf(Control? container)
+    {
+        if (container is null) return null;
+        foreach (Control c in container.Controls)
+        {
+            if (c is { CanSelect: true, TabStop: true, Visible: true, Enabled: true }) return c;
+            if (FirstFocusableLeaf(c) is { } nested) return nested;
+        }
+        return null;
+    }
 }
 
 /// <summary>