* feat: add local chat fork command
* docs: add chat chain fragment for fork command
* feat(chat): persist fork point metadata
Record the copied child message that marks the fork boundary and surface it through resume/session client state.
* feat(chat): show fork timeline divider
Render fork lineage inline after the copied fork point and link back to the original session with in-app switching.
* fix(chat): use branch title and trim fork divider
Default fork titles now use branch: <original title>; the fork divider uses a branch icon and relies on the parent title link instead of a duplicate view-original button.
* fix(chat): preserve fork divider hydration metadata
* test(chat): accept fork command alias in registry contract
---------
Co-authored-by: ekko <152005280+EKKOLearnAI@users.noreply.github.com>
ekko