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/sidebar-project-row-model.test.ts

@@ -1,9 +1,12 @@
 import { describe, expect, it } from "vitest";
-import { buildSidebarProjectRowModel } from "./sidebar-project-row-model";
 import type {
   SidebarProjectEntry,
   SidebarWorkspaceEntry,
 } from "@/hooks/use-sidebar-workspaces-list";
+import {
+  buildSidebarProjectRowModel,
+  resolveSidebarProjectIconTarget,
+} from "./sidebar-project-row-model";
 
 function workspace(overrides: Partial<SidebarWorkspaceEntry> = {}): SidebarWorkspaceEntry {
   return {
@@ -11,6 +14,7 @@ function workspace(overrides: Partial<SidebarWorkspaceEntry> = {}): SidebarWorks
     serverId: "srv",
     workspaceId: "ws-root",
     projectKey: "project-1",
+    projectName: "paseo",
     workspaceDirectory: "/repo",
     projectKind: "git",
     workspaceKind: "checkout",
@@ -37,7 +41,9 @@ function project(overrides: Partial<SidebarProjectEntry> = {}): SidebarProjectEn
     projectName: "paseo",
     projectKind,
     iconWorkingDir: "/repo",
-    canCreateWorktree: overrides.canCreateWorktree ?? projectKind === "git",
+    hosts: overrides.hosts ?? [
+      { serverId: "srv", iconWorkingDir: "/repo", canCreateWorktree: projectKind === "git" },
+    ],
     workspaces: [workspace()],
     ...overrides,
   };
@@ -56,7 +62,7 @@ describe("buildSidebarProjectRowModel", () => {
     expect(result).toEqual({
       kind: "project_section",
       chevron: "collapse",
-      trailingAction: "none",
+      trailingAction: { kind: "none" },
     });
   });
 
@@ -72,7 +78,29 @@ describe("buildSidebarProjectRowModel", () => {
     expect(result).toEqual({
       kind: "project_section",
       chevron: "expand",
-      trailingAction: "new_worktree",
+      trailingAction: {
+        kind: "new_worktree",
+        target: { serverId: "srv", iconWorkingDir: "/repo" },
+      },
+    });
+  });
+
+  it("targets the project host, not route state, for new worktree actions", () => {
+    const result = buildSidebarProjectRowModel({
+      project: project({
+        hosts: [
+          { serverId: "host-a", iconWorkingDir: "/repo/a", canCreateWorktree: false },
+          { serverId: "host-b", iconWorkingDir: "/repo/b", canCreateWorktree: true },
+        ],
+      }),
+      collapsed: false,
+    });
+
+    expect(result).toMatchObject({
+      trailingAction: {
+        kind: "new_worktree",
+        target: { serverId: "host-b", iconWorkingDir: "/repo/b" },
+      },
     });
   });
 
@@ -91,10 +119,26 @@ describe("buildSidebarProjectRowModel", () => {
     expect(result).toEqual({
       kind: "project_section",
       chevron: "expand",
-      trailingAction: "new_worktree",
+      trailingAction: {
+        kind: "new_worktree",
+        target: { serverId: "srv", iconWorkingDir: "/repo" },
+      },
     });
   });
 
+  it("resolves project icons from the project host, not the focused host", () => {
+    const iconTarget = resolveSidebarProjectIconTarget(
+      project({
+        hosts: [
+          { serverId: "host-b", iconWorkingDir: "/repo/b", canCreateWorktree: true },
+          { serverId: "host-a", iconWorkingDir: "/repo/a", canCreateWorktree: true },
+        ],
+      }),
+    );
+
+    expect(iconTarget).toEqual({ serverId: "host-b", iconWorkingDir: "/repo/b" });
+  });
+
   it("renders an empty project as an expandable section", () => {
     const result = buildSidebarProjectRowModel({
       project: project({ projectKind: "git", workspaces: [] }),
@@ -104,7 +148,10 @@ describe("buildSidebarProjectRowModel", () => {
     expect(result).toEqual({
       kind: "project_section",
       chevron: "collapse",
-      trailingAction: "new_worktree",
+      trailingAction: {
+        kind: "new_worktree",
+        target: { serverId: "srv", iconWorkingDir: "/repo" },
+      },
     });
   });
 });