full_res_preview test: wait again when the software rasterizer outlasts egui_kittest's 10 s render wait

test (windows-latest) fails on main in adjustment_layer_drag_previews_at_full_resolution_when_low_res_is_off
with "PollError: The requested Wait timed out before the submission was completed.": egui_kittest
waits at most 10 s for the GPU, and on the Windows runner the adapter is WARP, where the first
full-resolution composite of the 6 MP test document can take longer. The submitted work still
completes, so the pixel read now waits up to three times; the assertions are unchanged.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01UHgFEHEsefoQoBParH47JA

crates/ui-egui/tests/full_res_preview.rs

@@ -87,7 +87,10 @@ fn row(h: &mut Harness) -> Vec<i32> {
         let app = h.state();
         photocraft_ui_egui::rulers::content_rect(app, app.last_canvas_rect)
     };
-    let img = h.render().expect("render");
+    // egui_kittest waits 10 s for the GPU. Windows CI renders on WARP, a software rasterizer,
+    // where the first full-resolution composite of this 6 MP document can take longer; the
+    // submitted work still finishes, so wait for it again instead of failing.
+    let img = (0..3).find_map(|_| h.render().ok()).expect("render");
     let (x0, y) = (canvas.min.x as u32 + 20, canvas.min.y as u32 + 40);
     (x0..x0 + 300)
         .map(|x| {