Merge branch 'stack/agent-profiles-5-web-ui' into stack/agent-profiles-8-authoring

Authoring meets standing mounts: write() and remove() drop the standing
pointer so the NEXT session composes the edited roster, while every session
already joined keeps the generation it runs on — a superseded generation is
never disposed while the process lives. The settings-dialog golden re-records
with this layer's Agent Preset nav entry, which the incoming layer-3 record
had overwritten.

apps/web/tests/seeded-history.e2e.ts

@@ -236,14 +236,13 @@ describe('web e2e: seeded history renders through cold resume', () => {
     // The seed carries a session/title event: the title unit is host-plane, so
     // it folds the detached log and serves the value with nothing composed.
     expect(typeof projections?.values.title).toBe('string')
-    // `todos` is NOT here, and that is the contract rather than a gap. Its unit
-    // is registered by `tool-todo` inside an agent's preset, so a detached
-    // session yields it from exactly one place: a durable checkpoint written
-    // while the session was live. This seed was written straight to persistence
-    // and never ran, so it recorded none — and the answer no longer depends on
-    // whether some UNRELATED session happens to be composed right now, which is
-    // the whole reason the checkpoint row carries its own view.
-    expect(projections?.values).not.toHaveProperty('todos')
+    // `todos` IS here, as its empty fold (null). Its unit is registered by
+    // `tool-todo` inside the default preset's STANDING mount, which the read
+    // itself ensures — deterministically, not because some unrelated session
+    // happens to be composed. A present-but-null key is what keeps the
+    // client's "omitted key = capability absent → clear the row" rule from
+    // wiping preset-owned projections on cold reads.
+    expect(projections?.values).toHaveProperty('todos', null)
   })
 
   it.skipIf(MODE === 'record')('lists the seeded session cold and renders its history from the log', async () => {

apps/web/tests/snapshots/models-settings/declared.expected.md

@@ -7,6 +7,9 @@
     - button "模型":
       - img
       - text: 模型
+    - button "Agent 预设":
+      - img
+      - text: Agent 预设
   - button "打开配置文件"
   - button "关闭":
     - img