Fix workspace navigation regression on web (#772)

Centralize workspace navigation behind a small route-derived API so the workspace shell reads active selection from the current Expo Router route instead of a separately synchronized store.

Remove the stale layout-driven active-workspace write that regressed web after 02e5b564.

packages/app/src/utils/workspace-archive-navigation.test.ts

@@ -3,10 +3,6 @@ import { afterEach, describe, expect, it, vi } from "vitest";
 import { buildWorkspaceArchiveRedirectRoute } from "@/utils/workspace-archive-navigation";
 import type { WorkspaceDescriptor } from "@/stores/session-store";
 import { useSessionStore } from "@/stores/session-store";
-import {
-  activateNavigationWorkspaceSelection,
-  syncNavigationActiveWorkspace,
-} from "@/stores/navigation-active-workspace-store";
 import { redirectIfArchivingActiveWorkspace } from "@/utils/sidebar-workspace-archive-redirect";
 
 const { replaceMock } = vi.hoisted(() => ({
@@ -96,7 +92,6 @@ describe("buildWorkspaceArchiveRedirectRoute", () => {
 describe("redirectIfArchivingActiveWorkspace", () => {
   afterEach(() => {
     replaceMock.mockClear();
-    syncNavigationActiveWorkspace({ current: null });
     useSessionStore.getState().clearSession("server-1");
   });
 
@@ -109,12 +104,11 @@ describe("redirectIfArchivingActiveWorkspace", () => {
         ["feature", workspace({ id: "feature", name: "feature" })],
       ]),
     );
-    activateNavigationWorkspaceSelection({ serverId: "server-1", workspaceId: "main" });
-
     expect(
       redirectIfArchivingActiveWorkspace({
         serverId: "server-1",
         workspaceId: "feature",
+        activeWorkspaceSelection: { serverId: "server-1", workspaceId: "main" },
       }),
     ).toBe(false);
 
@@ -130,12 +124,11 @@ describe("redirectIfArchivingActiveWorkspace", () => {
         ["feature", workspace({ id: "feature", name: "feature" })],
       ]),
     );
-    activateNavigationWorkspaceSelection({ serverId: "server-1", workspaceId: "feature" });
-
     expect(
       redirectIfArchivingActiveWorkspace({
         serverId: "server-1",
         workspaceId: "feature",
+        activeWorkspaceSelection: { serverId: "server-1", workspaceId: "feature" },
       }),
     ).toBe(true);