Merge sidebar workspaces across all connected hosts (#1538)

* Merge workspaces across all hosts in the sidebar

Replace per-host sidebar sections with a single merged project list.
Projects that exist on multiple hosts (matched by projectKey) are
collapsed into one row. Host identity is surfaced via:

- A status-only footer pill showing online/offline host counts
- Hover cards with a mandatory host row on every workspace entry
- Subtitles showing the host name when a project spans >1 host
- A host filter in the grouping dropdown (not a sidebar switcher)

Order and group-mode stores migrated from per-server to global keys
with zustand persist migrations. New-workspace screen now shows a
merged project list with a host selector combobox.

Key files:
- workspace-structure.ts: merge algorithm by projectKey
- sidebar-view-store.ts / sidebar-order-store.ts: global state
- sidebar-workspace-list.tsx: context-based subtitle injection
- new-workspace-screen.tsx: host selector in footer row

* Add host filtering to the merged sidebar

The sidebar now merges workspaces from every connected host, so a single
global "active host" no longer fits. Host selection becomes explicit per
action via a host chooser, and agent history pages across all hosts at
once. Removes the active-host / active-server-id model and the
all-agents-list hook that fed it.

* Fix rebase fallout: translate archive host error, update stale workspace-key test

archiveWorkspacesOptimistically used a raw "Host is not connected" string
that the i18n completeness test forbids; route it through i18n.t with the
existing hostDisconnected key. The selectors memoization test asserted
un-prefixed workspace keys, but merged-sidebar keys are serverId-prefixed.

* Fix sidebar review fallout

* Address sidebar review followups

* Fix sidebar workspace identity migration

* Address sidebar review followups

* Handle partial host history failures

* Fix merged sidebar project removal and E2E drift

* Restore history routes and project removal shape

* Remove sidebar host context plumbing

* Tighten sidebar status and host filter state

* Keep new workspace project selection host-compatible

* Migrate sidebar view storage

* Streamline host selection flows

* Update all-host history on archive

* Fix empty project sidebar action

Code regression: the main merge dropped the empty-project New workspace child row while keeping the empty project persistence contract. Restore the row using the project host target so the sidebar stays aligned with the no-host-selection model.

* Fix Japanese shortcut translation key

Stale-base integration: main added the Japanese locale after this branch added cycleAgentMode to the English shortcut help map. Merging main exposed the missing ja key in CI typecheck and resources.test.

* Fix Playwright speech teardown race

packages/app/src/hooks/use-archive-agent.test.ts

@@ -3,7 +3,7 @@ import { QueryClient } from "@tanstack/react-query";
 import { beforeEach, describe, expect, it } from "vitest";
 import type { Agent } from "@/stores/session-store";
 import { useSessionStore } from "@/stores/session-store";
-import { agentHistoryQueryKey } from "./agent-history-query-key";
+import { agentHistoryQueryKey, allAgentHistoryQueryKey } from "./agent-history-query-key";
 import {
   applyArchivedAgentCloseResults,
   isAgentArchiving,
@@ -144,6 +144,17 @@ describe("useArchiveAgent", () => {
       ],
       pageParams: [null],
     });
+    queryClient.setQueryData(allAgentHistoryQueryKey(["server-a", "server-b"]), {
+      pages: [
+        {
+          agents: [
+            { id: "agent-1", serverId: "server-a", archivedAt: null },
+            { id: "agent-1", serverId: "server-b", archivedAt: null },
+          ],
+        },
+      ],
+      pageParams: [null],
+    });
 
     applyArchivedAgentCloseResults({
       queryClient,
@@ -174,6 +185,24 @@ describe("useArchiveAgent", () => {
       ],
       pageParams: [null],
     });
+    expect(
+      queryClient.getQueryState(allAgentHistoryQueryKey(["server-a", "server-b"]))?.isInvalidated,
+    ).toBe(true);
+    expect(queryClient.getQueryData(allAgentHistoryQueryKey(["server-a", "server-b"]))).toEqual({
+      pages: [
+        {
+          agents: [
+            {
+              id: "agent-1",
+              serverId: "server-a",
+              archivedAt: new Date("2026-04-01T04:00:00.000Z"),
+            },
+            { id: "agent-1", serverId: "server-b", archivedAt: null },
+          ],
+        },
+      ],
+      pageParams: [null],
+    });
   });
 
   it("can apply archived agent close results without invalidating cached lists", () => {
@@ -194,6 +223,10 @@ describe("useArchiveAgent", () => {
       ],
       pageParams: [null],
     });
+    queryClient.setQueryData(allAgentHistoryQueryKey(["server-a"]), {
+      pages: [{ agents: [{ id: "agent-1", serverId: "server-a", archivedAt: null }] }],
+      pageParams: [null],
+    });
 
     applyArchivedAgentCloseResults({
       queryClient,
@@ -205,6 +238,9 @@ describe("useArchiveAgent", () => {
     expect(queryClient.getQueryState(["sidebarAgentsList", "server-a"])?.isInvalidated).toBe(false);
     expect(queryClient.getQueryState(["allAgents", "server-a"])?.isInvalidated).toBe(false);
     expect(queryClient.getQueryState(agentHistoryQueryKey("server-a"))?.isInvalidated).toBe(false);
+    expect(queryClient.getQueryState(allAgentHistoryQueryKey(["server-a"]))?.isInvalidated).toBe(
+      false,
+    );
     expect(queryClient.getQueryData(agentHistoryQueryKey("server-a"))).toEqual({
       pages: [
         {
@@ -213,5 +249,19 @@ describe("useArchiveAgent", () => {
       ],
       pageParams: [null],
     });
+    expect(queryClient.getQueryData(allAgentHistoryQueryKey(["server-a"]))).toEqual({
+      pages: [
+        {
+          agents: [
+            {
+              id: "agent-1",
+              serverId: "server-a",
+              archivedAt: new Date("2026-04-01T04:00:00.000Z"),
+            },
+          ],
+        },
+      ],
+      pageParams: [null],
+    });
   });
 });