feat(web): add subagent conversation transport

packages/client/ui-workspace/tests/tree.spec.ts

@@ -17,7 +17,7 @@ const list = (...items: SessionSummary[]): SessionListState => ({
   ids: items.map(item => item.id),
   byId: Object.fromEntries(items.map(item => [item.id, item])),
   current: undefined,
-  phase: 'ready',
+  phase: 'ready', subagentsByParent: {}, currentAddress: undefined,
 })
 const workspace = (id: string, sessionIds: string[], title = id): WorkspaceView => ({
   workspaceId: wid(id), path: `/projects/${id}`, title,

packages/client/ui-workspace/tests/workspace-browser.spec.tsx

@@ -29,6 +29,8 @@ const sessionState = (items: readonly SessionSummary[], overrides: Partial<Sessi
   byId: Object.fromEntries(items.map(item => [item.id, item])),
   current: undefined,
   phase: 'ready',
+  subagentsByParent: {},
+  currentAddress: undefined,
   ...overrides,
 })
 const workspace = (id: string, sessionIds: string[], title = id): WorkspaceView => ({

packages/client/ui-workspace/tests/workspace-picker.spec.tsx

@@ -28,7 +28,7 @@ function hook<T>(snapshot: T) {
   return function select<S>(selector: (state: T) => S): S { return selector(snapshot) }
 }
 const sessions: SessionListState = {
-  ids: [], byId: {}, current: undefined, phase: 'ready',
+  ids: [], byId: {}, current: undefined, phase: 'ready', subagentsByParent: {}, currentAddress: undefined,
 }
 const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState => ({
   items, archivedSessionIds: [], state: 'idle', phase: 'ready', error: null, baselinesReady: true,