fix(downloads): make package disclosure motion visible

Keep the explicitly requested 300 ms package transition active when Chromium reports reduced motion, and separate the prepared and active disclosure states by a painted frame. Add focused regression coverage and an opt-in motion mode for the visual harness while keeping normal captures deterministic.

tests/downloads-view.test.tsx

@@ -23,6 +23,7 @@ import {
   activateDownloadDisclosureTransition,
   mergeDownloadDisclosureRows,
   prepareDownloadDisclosureTransition,
+  scheduleDownloadDisclosureActivation,
   stableDownloadDisclosureRows
 } from "../src/renderer/views/downloads/download-disclosure-transition";
 import {
@@ -224,6 +225,32 @@ describe("virtualisierte Paketanimation", () => {
     renderLimit: 100
   }));
 
+  it("zeichnet den Startzustand in einem eigenen Frame vor der Aktivierung", () => {
+    const frames: FrameRequestCallback[] = [];
+    const cancelled: number[] = [];
+    const activated = vi.fn();
+    let frameId = 0;
+    const requestFrame = vi.fn((callback: FrameRequestCallback) => {
+      frames.push(callback);
+      frameId += 1;
+      return frameId;
+    });
+    const cancelFrame = vi.fn((frame: number) => cancelled.push(frame));
+
+    const cancel = scheduleDownloadDisclosureActivation(requestFrame, cancelFrame, activated);
+
+    expect(activated).not.toHaveBeenCalled();
+    expect(frames).toHaveLength(1);
+    frames.shift()?.(16);
+    expect(activated).not.toHaveBeenCalled();
+    expect(frames).toHaveLength(1);
+    frames.shift()?.(32);
+    expect(activated).toHaveBeenCalledTimes(1);
+
+    cancel();
+    expect(cancelled).toContain(2);
+  });
+
   it("fährt neue Unterzeilen von null auf ihre feste Höhe aus und verschiebt Folgepakete unter stabilen IDs", () => {
     const collapsed = logicalRows([packageA.id]);
     const expanded = logicalRows([]);
@@ -246,6 +273,13 @@ describe("virtualisierte Paketanimation", () => {
     ]);
   });
 
+  it("behält die ausdrücklich gewünschte Paketbewegung auch bei reduzierten Systemanimationen bei", () => {
+    const css = fs.readFileSync(path.join(process.cwd(), "src/renderer/views/downloads/downloads.css"), "utf8");
+
+    expect(css).toMatch(/@media \(prefers-reduced-motion: reduce\)[\s\S]*\.downloads-virtual-spacer\s*\{[^}]*transition-duration:\s*300ms !important;/s);
+    expect(css).toMatch(/@media \(prefers-reduced-motion: reduce\)[\s\S]*\.downloads-virtual-row\s*\{[^}]*transition-duration:\s*300ms, 300ms, 300ms !important;/s);
+  });
+
   it("behält ausfahrende Unterzeilen bis zum Animationsende und reduziert ihre Höhe auf null", () => {
     const expanded = logicalRows([]);
     const collapsed = logicalRows([packageA.id]);

tests/visual/index.html

@@ -4,10 +4,13 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>Multi Debrid Downloader Visual Harness</title>
+    <script>
+      if (new URLSearchParams(location.search).has("motion")) document.documentElement.dataset.visualMotion = "true";
+    </script>
     <style>
-      *,
-      *::before,
-      *::after {
+      html:not([data-visual-motion="true"]) *,
+      html:not([data-visual-motion="true"]) *::before,
+      html:not([data-visual-motion="true"]) *::after {
         animation: none !important;
         caret-color: transparent !important;
         transition: none !important;