Lay git's own diff out to the width the layout gives the view

Changing the screen mode renders the main view again, and so does
anything else that changes its size along with what it shows. With git's
own diff, that render laid a commit's diffstat out to the width the view
had before. The graph then wrapped onto rows of its own in a view that
got narrower, and stopped short in one that got wider.

A diff renderer's render is created after the layout pass, since only
the layout settles the view's size, and takes its width there. git's own
diff took its width straight away instead, when the render was asked
for. Create its task after the layout as well.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pkg/gui/tasks_adapter.go

@@ -27,11 +27,17 @@ func (gui *Gui) newCmdTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 	// thumb to shrink and snap back as the rest loads.
 	view.FreezeScrollbarHeight()
 
-	// Snapshot the view width here, on the UI thread, so the task goroutine
-	// doesn't read the view's live dimensions while it streams output.
-	spec := renderSpec{view: view, cmd: cmd, width: view.InnerWidth()}
+	// The command lays its output out to the width of the view (git's diffstat
+	// graph does), and only the layout settles that, so the task is created after
+	// it, as a diff renderer's is. Taking the width there, on the UI thread, also
+	// keeps the task goroutine from reading the view's live dimensions while it
+	// streams output.
+	gui.afterLayout(func() error {
+		spec := renderSpec{view: view, cmd: cmd, width: view.InnerWidth()}
+		return gui.newTaskForRender(spec, prefix, cmdStr, gui.plainRender)
+	})
 
-	return gui.newTaskForRender(spec, prefix, cmdStr, gui.plainRender)
+	return nil
 }
 
 // plainRender runs the command as it is, with its output going straight into

pkg/integration/tests/diff/stat_follows_a_screen_mode_change.go

@@ -49,10 +49,7 @@ var StatFollowsAScreenModeChange = NewIntegrationTest(NewIntegrationTestArgs{
 		t.Views().Main().
 			ContainsViewLines(
 				Contains("file1 | 200"),
-				/* EXPECTED:
 				Contains("1 file changed"),
-				ACTUAL: */
-				MatchesRegexp(`^\++$`),
 			)
 	},
 })