Support changing reasoning effort (#2435)

https://github.com/user-attachments/assets/50198ee8-5915-47a3-bb71-69af65add1ef

Building up on #2431 #2428

codex-rs/tui/src/app.rs

@@ -382,6 +382,11 @@ impl App<'_> {
                             self.app_event_tx.send(AppEvent::CodexOp(Op::Compact));
                         }
                     }
+                    SlashCommand::Model => {
+                        if let AppState::Chat { widget } = &mut self.app_state {
+                            widget.open_model_popup();
+                        }
+                    }
                     SlashCommand::Quit => {
                         break;
                     }
@@ -499,6 +504,16 @@ impl App<'_> {
                         widget.apply_file_search_result(query, matches);
                     }
                 }
+                AppEvent::UpdateReasoningEffort(effort) => {
+                    if let AppState::Chat { widget } = &mut self.app_state {
+                        widget.set_reasoning_effort(effort);
+                    }
+                }
+                AppEvent::UpdateModel(model) => {
+                    if let AppState::Chat { widget } = &mut self.app_state {
+                        widget.set_model(model);
+                    }
+                }
             }
         }
         terminal.clear()?;