fix(web): stabilize nested subagent navigation

packages/client/runtime/tests/manager.spec.ts

@@ -426,6 +426,47 @@ describe('subagent catalogs', () => {
       { kind: 'child', id: S2, hasChildren: false },
     ])
   })
+
+  it('preserves a live expandability hint across only the older in-flight catalog response', async () => {
+    const api = new FakeApiClient()
+    const root = 'fk-root' as SessionId
+    const response = deferred<Awaited<ReturnType<FakeApiClient['onSubagentList']>>>()
+    api.onSubagentList = () => response.promise
+    const manager = new SessionManager(api)
+    const refresh = manager.refreshSubagents(root)
+
+    manager.handleHostEnvelope({
+      rpcId: 'nested-subagent' as never,
+      payload: {
+        type: 'host/session-added', sessionId: 'fk-grandchild' as SessionId,
+        parentSessionId: S1, origin: 'subagent', blank: false,
+      },
+    })
+    response.resolve(ok({
+      entries: [{
+        kind: 'child', id: S1, mode: 'continuable', label: 'parent',
+        activity: 'inactive', hasChildren: false,
+      }] as never[],
+      parentAvailable: true,
+    }))
+    await refresh
+
+    expect(manager.getListSnapshot().subagentsByParent[root]?.entries).toMatchObject([
+      { kind: 'child', id: S1, hasChildren: true },
+    ])
+
+    api.onSubagentList = () => Promise.resolve(ok({
+      entries: [{
+        kind: 'child', id: S1, mode: 'continuable', label: 'parent',
+        activity: 'inactive', hasChildren: false,
+      }] as never[],
+      parentAvailable: true,
+    }))
+    await manager.refreshSubagents(root)
+    expect(manager.getListSnapshot().subagentsByParent[root]?.entries).toMatchObject([
+      { kind: 'child', id: S1, hasChildren: false },
+    ])
+  })
 })
 
 describe('remaining branches', () => {

packages/client/runtime/tests/sessions-service.spec.ts

@@ -3,8 +3,8 @@
  * with derived titles), the migrated current-selection account (open
  * validation, persisted mask semantics, cell resolution), scope-tree
  * lifecycle (lazy mint / frozen survival / removed teardown with staged
- * deferral — the stage follows list.current), binding identity, ancestry
- * walk, create.
+ * deferral — the stage follows list.current), binding identity, breadcrumb
+ * projection, create.
  */
 import { Context } from 'cordis'
 import { afterEach, describe, expect, it, vi } from 'vitest'
@@ -361,24 +361,8 @@ describe('slot-store scope prune hook', () => {
   })
 })
 
-describe('ancestry', () => {
-  it('walks only subagent lineage and includes its first ordinary owner', async () => {
-    const b = bench()
-    await feedList(b, [
-      { id: 'root', cwd: '/w/app' },
-      { id: 'fork', parentId: 'root' },
-      { id: 'child', parentId: 'fork', origin: 'subagent' },
-      { id: 'grandchild', parentId: 'child', origin: 'subagent' },
-      { id: 'orphan', parentId: 'ghost', origin: 'subagent' },
-    ])
-    expect(b.svc.ancestry(sid('fork')).map(s => s.id)).toEqual(['fork'])
-    expect(b.svc.ancestry(sid('child')).map(s => s.id)).toEqual(['fork', 'child'])
-    expect(b.svc.ancestry(sid('grandchild')).map(s => s.id)).toEqual(['fork', 'child', 'grandchild'])
-    expect(b.svc.ancestry(sid('orphan')).map(s => s.id)).toEqual(['orphan'])
-    expect(b.svc.ancestry(sid('ghost'))).toEqual([])
-  })
-
-  it('retains a cold nested subagent route without retaining ancestor scopes', async () => {
+describe('catalog-addressed navigation', () => {
+  it('projects a directly opened descendant route without retaining ancestor scopes or addresses', async () => {
     const b = bench()
     b.api.onSubagentList = (payload) => {
       const { parentSessionId } = payload as { parentSessionId: SessionId }
@@ -402,26 +386,19 @@ describe('ancestry', () => {
       }
       return Promise.resolve(ok({ entries: [], parentAvailable: false }))
     }
-    await feedList(b, [
-      { id: 'root' },
-      { id: 'child', parentId: 'root', origin: 'subagent' },
-      { id: 'grandchild', parentId: 'child', origin: 'subagent' },
-    ])
+    await feedList(b, [{ id: 'root' }])
     await b.svc.refreshSubagents(sid('root'))
-    b.svc.openSubagent({
-      parentSessionId: sid('root'), childSessionId: sid('child'), mode: 'continuable',
-    })
     await b.svc.refreshSubagents(sid('child'))
     b.svc.openSubagent({
       parentSessionId: sid('child'), childSessionId: sid('grandchild'), mode: 'continuable',
     })
 
-    await feedList(b, [{ id: 'root' }])
     const list = b.svc.list.getSnapshot()
     expect(list.ids).toEqual([sid('root')])
-    expect(b.svc.ancestry(sid('grandchild')).map(summary => summary.id))
-      .toEqual([sid('root'), sid('child'), sid('grandchild')])
+    expect(list.byId[sid('child')]).toMatchObject({ parentId: sid('root'), origin: 'subagent' })
+    expect(list.byId[sid('grandchild')]).toMatchObject({ parentId: sid('child'), origin: 'subagent' })
     expect(b.svc.binding(sid('child'))).toBeUndefined()
+    expect(b.svc.subagentAddress(sid('child'))).toBeUndefined()
 
     b.svc.open(sid('child'))
     expect(b.svc.list.getSnapshot().current).toBe(sid('child'))