fix(tui): request repaint after catch-up model sync

setModel() invalidates the render cache but doesn't schedule a paint.
The initial forced startup paint (line 1104) may have already rendered
the old model, so the catch-up #updateWelcomeModel() must explicitly
request a render — matching #updateWelcomeLspServers().

packages/coding-agent/src/modes/interactive-mode.ts

@@ -4440,6 +4440,7 @@ export class InteractiveMode implements InteractiveModeContext {
 			this.session.model?.name ?? "Unknown",
 			this.session.model?.provider ?? "Unknown",
 		);
+		this.ui.requestRender();
 	}
 
 	#updateWelcomeLspServers(): void {