feat: open Changes as a workspace tab (#2298)

Open the complete working comparison in a desktop workspace tab while preserving inline sidebar diffs when the tab is closed.

Working and commit comparisons share one diff panel, and workspace layout is the sole owner of live tab persistence and identity.

Refs #1520

packages/app/src/workspace/use-workspace-archive.ts

@@ -8,11 +8,8 @@ import {
   type WorktreeArchiveWarningLabels,
 } from "@/git/worktree-archive-warning";
 import type { WorkspaceDescriptor } from "@/stores/session-store";
-import {
-  buildWorkspaceTabPersistenceKey,
-  useWorkspaceLayoutStore,
-} from "@/stores/workspace-layout-store";
-import { useWorkspaceTabsStore } from "@/stores/workspace-tabs-store";
+import { useWorkspaceLayoutStore } from "@/stores/workspace-layout-store";
+import { buildWorkspaceTabPersistenceKey } from "@/workspace-tabs/model";
 import { archiveWorkspaceOptimistically } from "@/workspace/workspace-archive";
 
 function purgeArchivedWorkspaceState(input: { serverId: string; workspaceId: string }): void {
@@ -20,7 +17,6 @@ function purgeArchivedWorkspaceState(input: { serverId: string; workspaceId: str
   if (workspaceKey) {
     useWorkspaceLayoutStore.getState().purgeWorkspace(workspaceKey);
   }
-  useWorkspaceTabsStore.getState().purgeWorkspace(input);
 }
 
 export interface ArchiveWorkspaceInput {