diag #387: permanent evidence lines on the resize chain (event, swapchain recreate, resolution apply)

Three rare-event log lines so any future resize report is diagnosable
from the launch log alone: 'window: framebuffer resize event WxH',
'vulkan: swapchain recreated WxH ok=', and 'display: resolution pick
WxH (window was WxH)'. An instrumented live run on the Windows AMD box
shows the full chain firing for both the programmatic resolution apply
and external window resizes, and screen captures at 784x561 vs 1584x861
confirm fixed-pixel UI with a true pixel-count re-render.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Settings/RuntimeSettingsTargets.cs

@@ -60,6 +60,10 @@ internal sealed class SilkRuntimeDisplayWindowTarget : IRuntimeDisplayWindowTarg
             TryParseResolution(display.Resolution, out int width, out int height);
         if (haveResolution && (_window.Size.X != width || _window.Size.Y != height))
         {
+            // #387 evidence line (permanent): the resolution-pick write path.
+            Console.WriteLine(
+                $"display: resolution pick {width}x{height} " +
+                $"(window was {_window.Size.X}x{_window.Size.Y})");
             _window.Size = new Vector2D<int>(width, height);
         }