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/utils/host-routes.test.ts

@@ -5,6 +5,10 @@ import {
   buildHostRootRoute,
   buildHostWorkspaceOpenRoute,
   buildHostWorkspaceRoute,
+  buildOpenProjectRoute,
+  resolveKnownHostRoute,
+  buildSessionsRoute,
+  buildSettingsAddHostRoute,
   buildProjectSettingsRoute,
   buildProjectsSettingsRoute,
   decodeFilePathFromPathSegment,
@@ -16,6 +20,7 @@ import {
   parseHostWorkspaceOpenIntentFromPathname,
   parseHostWorkspaceRouteFromPathname,
   parseWorkspaceOpenIntent,
+  stripHostWorkspaceRouteEchoSearch,
 } from "./host-routes";
 
 describe("parseHostAgentRouteFromPathname", () => {
@@ -122,6 +127,28 @@ describe("workspace route parsing", () => {
     );
   });
 
+  it("strips route params repeated as workspace route search params", () => {
+    expect(
+      stripHostWorkspaceRouteEchoSearch(
+        "/h/local/workspace/164?serverId=local&workspaceId=164&open=agent%3Aagent-1#pane",
+      ),
+    ).toBe("/h/local/workspace/164?open=agent%3Aagent-1#pane");
+  });
+
+  it("keeps non-route workspace search params", () => {
+    expect(stripHostWorkspaceRouteEchoSearch("/h/local/workspace/164?workspaceId=other")).toBe(
+      "/h/local/workspace/164?workspaceId=other",
+    );
+  });
+
+  it("strips encoded workspace route echoes", () => {
+    expect(
+      stripHostWorkspaceRouteEchoSearch(
+        "/h/local/workspace/b64_L3RtcC9yZXBv?workspaceId=%2Ftmp%2Frepo",
+      ),
+    ).toBe("/h/local/workspace/b64_L3RtcC9yZXBv");
+  });
+
   it("builds a global new workspace route without a source directory", () => {
     expect(buildHostNewWorkspaceRoute("local")).toBe("/h/local/new");
   });
@@ -153,6 +180,14 @@ describe("workspace route parsing", () => {
 });
 
 describe("projects settings routes", () => {
+  it("buildSettingsAddHostRoute opens settings with the add-host flag", () => {
+    expect(buildSettingsAddHostRoute()).toBe("/settings/general?addHost=1");
+  });
+
+  it("buildSettingsAddHostRoute accepts a repeatable intent id", () => {
+    expect(buildSettingsAddHostRoute("retry 1")).toBe("/settings/general?addHost=retry%201");
+  });
+
   it("buildProjectsSettingsRoute returns /settings/projects", () => {
     expect(buildProjectsSettingsRoute()).toBe("/settings/projects");
   });
@@ -177,6 +212,12 @@ describe("projects settings routes", () => {
   });
 });
 
+describe("global routes", () => {
+  it("buildSessionsRoute returns the all-host Sessions route", () => {
+    expect(buildSessionsRoute()).toBe("/sessions");
+  });
+});
+
 describe("host settings section slugs", () => {
   it("keeps current host settings sections", () => {
     expect(normalizeHostSectionSlug("connections")).toBe("connections");
@@ -192,3 +233,32 @@ describe("host settings section slugs", () => {
     expect(normalizeHostSectionSlug("daemon")).toBe("host");
   });
 });
+
+describe("resolveKnownHostRoute", () => {
+  it("renders when the route host is still saved", () => {
+    expect(
+      resolveKnownHostRoute({
+        routeServerId: "srv-current",
+        hosts: [{ serverId: "srv-current" }, { serverId: "srv-next" }],
+      }),
+    ).toEqual({ kind: "render" });
+  });
+
+  it("sends removed host routes to the host-agnostic open project screen", () => {
+    expect(
+      resolveKnownHostRoute({
+        routeServerId: "srv-removed",
+        hosts: [{ serverId: "srv-next" }],
+      }),
+    ).toEqual({ kind: "redirect", href: buildOpenProjectRoute() });
+  });
+
+  it("sends host routes to welcome when no hosts are saved", () => {
+    expect(
+      resolveKnownHostRoute({
+        routeServerId: "srv-removed",
+        hosts: [],
+      }),
+    ).toEqual({ kind: "redirect", href: "/welcome" });
+  });
+});