Release v0.51.279 — Release IU (stage-p3h — preserve Activity/streaming turn on mid-stream scroll #3665) (#3686)

* fix(streaming): preserve Activity + streaming turn when loading earlier messages mid-stream (#3665, #3346)

Co-authored-by: mysoul12138 <839465496@qq.com>

* docs(changelog): v0.51.279 — Release IU (stage-p3h)

---------

Co-authored-by: nesquena-hermes <[email protected]>
Co-authored-by: mysoul12138 <839465496@qq.com>

CHANGELOG.md

@@ -3,6 +3,11 @@
 
 ## [Unreleased]
 
+## [v0.51.279] — 2026-06-05 — Release IU (stage-p3h — preserve Activity/streaming turn on mid-stream scroll)
+
+### Fixed
+- **Loading earlier messages during an active stream no longer wipes the Activity panel or the current streaming turn.** Two causes: (1) the message merge/dedup keys didn't include `tool_calls`, so assistant messages invoking *different* tools with identical empty content and same-second timestamps collapsed into one — dropping every state.db tool-call after the first the sidecar registered; (2) `_syncToolCallsForLoadedMessages` cleared `S.toolCalls` while `S.busy` blocked the `renderMessages` rebuild. `tool_calls` is now part of the merge/dedup/visible keys (with a preservation branch so distinct tool invocations within the sidecar timestamp window aren't skipped), and the frontend keeps the live tool-call/streaming state when paging in history. (#3665, @mysoul12138; fixes #3346)
+
 ## [v0.51.278] — 2026-06-05 — Release IT (stage-p3g — repair inline PDF preview)
 
 ### Fixed