feat: rebuild workspaces as the reference plugin

src/ui/tests/shell/shell-layout.test.ts

@@ -358,11 +358,49 @@ describe("plugin tab types in layouts", () => {
     expect(snapshots.map((s) => s.type)).toEqual(["terminal"]);
   });
 
-  it("leaves out a plugin tab type nobody registered", () => {
+  it("keeps a plugin tab type nobody registered, so a disabled plugin loses nothing", () => {
     const { snapshots } = buildWorkspaceTabSnapshots([
-      makeTab({ id: "x", type: "some-plugin-tab" }),
+      makeTab({ id: "x", type: "some-plugin-tab", data: { a: 1 } }),
+      makeTab({ id: "d", type: "dashboard" }),
+      makeTab({ id: "h", type: "host-manager" }),
     ]);
-    expect(snapshots).toEqual([]);
+    expect(snapshots.map((s) => s.type)).toEqual(["some-plugin-tab"]);
+    expect(snapshotData(snapshots[0])).toEqual({ a: 1 });
+  });
+
+  it("reopens a hostless tab of a missing plugin as a placeholder", () => {
+    expect(
+      resolveWorkspaceTabTarget(
+        { slotId: "s", type: "some-plugin-tab", label: "Gone" },
+        [],
+      ),
+    ).toEqual({ kind: "singleton" });
+  });
+
+  it("reopens a missing plugin's host tab while its host exists", () => {
+    const host = makeHost({ syncId: "sync-1" });
+    expect(
+      resolveWorkspaceTabTarget(
+        {
+          slotId: "s",
+          type: "some-plugin-tab",
+          label: "Gone",
+          hostSyncId: "sync-1",
+        },
+        [host],
+      ),
+    ).toEqual({ kind: "host", host });
+    expect(
+      resolveWorkspaceTabTarget(
+        {
+          slotId: "s",
+          type: "some-plugin-tab",
+          label: "Gone",
+          hostSyncId: "sync-deleted",
+        },
+        [host],
+      ),
+    ).toEqual({ kind: "skip" });
   });
 
   it("carries a tab's plugin data and reads the older fleetId field", () => {

src/ui/tests/sidebar/rail-items.test.ts

@@ -2,6 +2,7 @@ import { afterEach, describe, expect, it } from "vitest";
 import { Boxes } from "lucide-react";
 import {
   hideableRailIds,
+  permittedRailItems,
   promotableIds,
   RAIL_ITEMS,
   RAIL_UTILITY_ITEMS,
@@ -230,3 +231,39 @@ describe("railItemLabel", () => {
     });
   });
 });
+
+describe("permittedRailItems", () => {
+  const items = [
+    { id: "open", icon: Boxes, labelKey: "nav.hosts" },
+    {
+      id: "gated",
+      icon: Boxes,
+      labelKey: "nav.hosts",
+      permission: "demo.use",
+    },
+  ];
+
+  it("hides an item gated on a permission the user lacks", () => {
+    const ids = permittedRailItems(items, {
+      loaded: true,
+      has: () => false,
+    }).map((item) => item.id);
+    expect(ids).toEqual(["open"]);
+  });
+
+  it("shows it once the user holds the permission", () => {
+    const ids = permittedRailItems(items, {
+      loaded: true,
+      has: (permission) => permission === "demo.use",
+    }).map((item) => item.id);
+    expect(ids).toEqual(["open", "gated"]);
+  });
+
+  it("keeps gated items hidden until permissions have loaded", () => {
+    const ids = permittedRailItems(items, {
+      loaded: false,
+      has: () => true,
+    }).map((item) => item.id);
+    expect(ids).toEqual(["open"]);
+  });
+});