fix(git): stop fs watcher before closing debounce timer

lua/git/repo.lua

@@ -117,12 +117,16 @@ function Repo:start_watcher()
 end
 
 function Repo:stop_watcher()
-    self.refresh_handle.close()
+    -- Stop the libuv watcher first so no further fs-events can trigger
+    -- self:refresh(); only then tear down the debounce handle. The reverse
+    -- order leaves a window where an in-flight watcher callback would call
+    -- a closed debounce timer.
     if self.watcher then
         self.watcher:stop()
         self.watcher:close()
         self.watcher = nil
     end
+    self.refresh_handle.close()
 end
 
 ---@param buf integer