* fix(server): bound shared-worktree fetch refreshes
* fix(server): preserve buffered git metadata events
* fix(server): cover remote ref selection changes
* fix(server): preserve narrow fetch echo routing
* fix(server): preserve ref updates during refresh
Keep normal refresh requeue semantics for watcher events that arrive while a ref-derived calculation is active, so a second same-ref movement cannot be mistaken for the original fetch echo.
* fix(server): narrow external fetch ref updates
Use authoritative fetch boundaries to separate watcher echoes from outside events, and retain remote ref names so packed-to-loose materialization from other Git clients stays narrow without weakening add/delete fallbacks.
