feat(downloads): animate priority reordering

Rename the package disclosure option to a general animations switch and use it for both disclosure and priority-order motion. Keep previously visible virtual rows mounted during reorders, animate measured start and target positions for 1.5 seconds, and cancel all motion immediately when the setting is disabled. Extend the isolated renderer fixture so enabled and disabled behavior can be measured without touching user download state.

tests/downloads-view.test.tsx

@@ -28,6 +28,12 @@ import {
   scheduleDownloadDisclosureActivation,
   stableDownloadDisclosureRows
 } from "../src/renderer/views/downloads/download-disclosure-transition";
+import {
+  DOWNLOAD_ORDER_TRANSITION_DURATION_MS,
+  getDownloadOrderTransitionPinnedIds,
+  getDownloadOrderTransformKeyframes,
+  isDownloadPackageOrderChange
+} from "../src/renderer/views/downloads/download-order-transition";
 import {
   DownloadsContent,
   DownloadsFooter,
@@ -241,12 +247,36 @@ describe("virtualisierte Paketanimation", () => {
     expect(prepared.rows.some((row) => row.type === "item-group")).toBe(false);
   });
 
-  it("deaktiviert auch die CSS-Bewegung der virtuellen Folgezeilen", () => {
-    const html = renderToStaticMarkup(<DownloadsContent actions={createActions()} model={withRuntime(createInput(), { animatePackageDisclosure: false })} />);
+  it("deaktiviert alle Downloadbewegungen über den allgemeinen Animationsschalter", () => {
+    const html = renderToStaticMarkup(<DownloadsContent actions={createActions()} model={withRuntime(createInput(), { animationsEnabled: false })} />);
     const css = readFileSync(path.join(process.cwd(), "src/renderer/views/downloads/downloads.css"), "utf8");
 
-    expect(html).toContain('class="downloads-table-body is-disclosure-motion-disabled"');
-    expect(css).toMatch(/\.downloads-table-body\.is-disclosure-motion-disabled \.downloads-virtual-spacer,\s*\.downloads-table-body\.is-disclosure-motion-disabled \.downloads-virtual-row\s*\{[^}]*transition:\s*none !important;/s);
+    expect(html).toContain('class="downloads-table-body is-download-motion-disabled"');
+    expect(css).toMatch(/\.downloads-table-body\.is-download-motion-disabled \.downloads-virtual-spacer,\s*\.downloads-table-body\.is-download-motion-disabled \.downloads-virtual-row\s*\{[^}]*transition:\s*none !important;/s);
+  });
+
+  it("pins only previously visible rows for a real priority reorder", () => {
+    expect(DOWNLOAD_ORDER_TRANSITION_DURATION_MS).toBe(1500);
+    expect(isDownloadPackageOrderChange(["a", "b", "c"], ["b", "c", "a"])).toBe(true);
+    expect(isDownloadPackageOrderChange(["a", "b"], ["a", "c"])).toBe(false);
+    expect(getDownloadOrderTransitionPinnedIds({
+      enabled: true,
+      previousOrder: ["a", "b", "c"],
+      nextOrder: ["b", "c", "a"],
+      previousVisibleIds: ["a", "a:items", "b"],
+      activePinnedIds: []
+    })).toEqual(["a", "a:items", "b"]);
+    expect(getDownloadOrderTransitionPinnedIds({
+      enabled: false,
+      previousOrder: ["a", "b", "c"],
+      nextOrder: ["b", "c", "a"],
+      previousVisibleIds: ["a", "b"],
+      activePinnedIds: ["c"]
+    })).toEqual([]);
+    expect(getDownloadOrderTransformKeyframes(240, 159, 315)).toEqual([
+      { transform: "translateY(84px)" },
+      { transform: "translateY(240px)" }
+    ]);
   });
 
   it("zeichnet den Startzustand in einem eigenen Frame vor der Aktivierung", () => {
@@ -681,7 +711,7 @@ function withRuntime(input: DownloadsModelInput, overrides: Record<string, unkno
     scheduleLabel: "",
     packageSpeedBps: { "package-a": 12_000_000 },
     disclosureRevision: 0,
-    animatePackageDisclosure: true,
+    animationsEnabled: true,
     editingPackageId: null,
     editingName: "",
     columnOrder: ["name", "size", "hoster", "progress"] as const,
@@ -1177,6 +1207,16 @@ describe("downloads App integration", () => {
     expect(source).toMatch(/disabled=\{allMatch\}[\s\S]{0,260}window\.rd\.setPackagePriority/);
   });
 
+  it("keeps previously visible package rows mounted while priority order glides", () => {
+    const source = readFileSync(new URL("../src/renderer/views/downloads/VirtualizedDownloadsBody.tsx", import.meta.url), "utf8").replaceAll("\r\n", "\n");
+
+    expect(source).toContain("getDownloadOrderTransitionPinnedIds");
+    expect(source).toContain("animateDownloadOrderRows");
+    expect(source).toContain("orderTransitionPinnedIdsRef.current");
+    expect(source).toContain("data-download-row-id={entry.id}");
+    expect(source).toContain("DOWNLOAD_ORDER_TRANSITION_DURATION_MS");
+  });
+
   it("updates the clipboard checkbox optimistically before IPC reconciliation", () => {
     const source = readFileSync(new URL("../src/renderer/App.tsx", import.meta.url), "utf8").replaceAll("\r\n", "\n");