feat(feedback): add the Web surface for message feedback

Consume the durable message-feedback sidecar from #2217 in the browser:
per-message Like/Dislike with an optional note, contributed through a
declared assistant-actions slot.

- carry MessageId on finalized AssistantMessageNode so a target is nameable
- declare conversation.chat.assistant-actions and render it in the
  IconActions row between copy and branch
- hold one FeedbackController per Session with per-item ifVersion CAS,
  reconciling a version-conflict from the reply's authoritative item
- mount messageFeedbackRemote alongside goalsRemote

packages/api/remotes/tsconfig.client.json

@@ -15,6 +15,9 @@
     {
       "path": "../../goal/goal"
     },
+    {
+      "path": "../../feedback/message-feedback"
+    },
     {
       "path": "../../typert/type-meta"
     }