Merge remote-tracking branch 'origin/master' into feat/todo-multi-in-progress

# Conflicts:
#	docs/core-data-structures/session.i18n.yaml
#	packages/client/ui-conversation/README.i18n.yaml

docs/core-data-structures/session.md

@@ -494,15 +494,8 @@ declare class Session {
    */
   deriveMessages(): Message[];
   /**
-   * Project a single event into the LLM message it derives to, or null when
-   * it produces none — a non-surface event (chunk, boundary, log-only record)
-   * or an empty-content assistant/message (which exists only to host usage).
-   * The per-node pure function {@link deriveMessages} folds over the surface;
-   * an external reconstructor (or the dev invariant) folds the same function
-   * over a log prefix's surface to rebuild the exact messages any request was
-   * built from (the reconstructability Agent Note). The returned message is
-   * the already frozen message nested in the event wrapper and shared by
-   * delivery, durable history, and model requests.
+   * Instance face of the pure per-node `deriveEventMessage` export from
+   * `surface.ts`.
    * @param event - the event to project.
    * @returns the derived message, or null when the event produces none.
    */