render • as dim (#4467)

<img width="988" height="686" alt="Screenshot 2025-09-29 at 3 28 30 PM"
src="https://github.com/user-attachments/assets/634a6e6f-cdc0-49af-97c1-096e871414bb"
/>

codex-rs/tui/src/exec_cell/render.rs

@@ -200,7 +200,7 @@ impl ExecCell {
             if self.is_active() {
                 spinner(self.active_start_time())
             } else {
-                "•".into()
+                "•".dim()
             },
             " ".into(),
             if self.is_active() {