feat(sidebar): show host name on every row in multi-host setups (#1775)

The host name previously appeared only in project grouping mode, and only
for projects shared across hosts. It now shows on every workspace row in
both project and status grouping modes whenever the sidebar spans more than
one host, so you can always tell which machine a workspace lives on. Status
rows read "Project · Host". Single-host setups are unchanged.

packages/app/src/hooks/sidebar-workspaces-view-model.test.ts

@@ -9,6 +9,7 @@ import {
   buildSidebarProjectsFromStructure,
   computeSidebarOrderUpdates,
   deriveSidebarLoadingState,
+  shouldShowSidebarHostLabels,
   type SidebarProjectEntry,
 } from "./sidebar-workspaces-view-model";
 
@@ -297,6 +298,63 @@ describe("shared sidebar workspace model", () => {
   });
 });
 
+describe("shouldShowSidebarHostLabels", () => {
+  it("is false with no visible projects", () => {
+    expect(shouldShowSidebarHostLabels([])).toBe(false);
+  });
+
+  it("is false when every project lives on a single host", () => {
+    const projects = buildSidebarProjectsFromStructure({
+      projects: [
+        project({ projectKey: "project-a", workspaceKeys: ["ws-1"] }),
+        project({ projectKey: "project-b", workspaceKeys: ["ws-2"] }),
+      ],
+    });
+
+    expect(shouldShowSidebarHostLabels(projects)).toBe(false);
+  });
+
+  it("is true when projects span separate hosts", () => {
+    const projects = buildSidebarProjectsFromStructure({
+      projects: [
+        project({
+          projectKey: "project-a",
+          hosts: [
+            { serverId: "host-a", iconWorkingDir: "/repo/project-a", canCreateWorktree: true },
+          ],
+          workspaceKeys: ["host-a:ws-1"],
+        }),
+        project({
+          projectKey: "project-b",
+          hosts: [
+            { serverId: "host-b", iconWorkingDir: "/repo/project-b", canCreateWorktree: true },
+          ],
+          workspaceKeys: ["host-b:ws-2"],
+        }),
+      ],
+    });
+
+    expect(shouldShowSidebarHostLabels(projects)).toBe(true);
+  });
+
+  it("is true for a single project shared across hosts", () => {
+    const projects = buildSidebarProjectsFromStructure({
+      projects: [
+        project({
+          projectKey: "getpaseo/paseo",
+          hosts: [
+            { serverId: "host-a", iconWorkingDir: "/repo/paseo", canCreateWorktree: true },
+            { serverId: "host-b", iconWorkingDir: "/repo/paseo", canCreateWorktree: true },
+          ],
+          workspaceKeys: ["host-a:main", "host-b:feature"],
+        }),
+      ],
+    });
+
+    expect(shouldShowSidebarHostLabels(projects)).toBe(true);
+  });
+});
+
 describe("computeSidebarOrderUpdates", () => {
   it("returns no updates when there are no visible projects", () => {
     const updates = computeSidebarOrderUpdates({