Report the configured TUI mode in codex doctor (#50200)

## What changed

Add `configured TUI mode` to the configuration details in human-readable and JSON doctor reports. Report `fullscreen` when `tui.fullscreen_transcript` is enabled and `scrollback` when it is disabled.

## Testing

Add an integration test covering both configuration values in JSON output and update the human-readable report snapshot to include the mode.

GitOrigin-RevId: beb62ddfa62a3516a64b5a69d5a41b257434f5d5

codex-rs/cli/src/doctor.rs

@@ -1113,6 +1113,14 @@ fn config_check(config: &Config) -> DoctorCheck {
         config.model.as_deref().unwrap_or("<default>")
     ));
     details.push(format!("model provider: {}", config.model_provider_id));
+    details.push(format!(
+        "configured TUI mode: {}",
+        if config.tui_fullscreen_transcript {
+            "fullscreen"
+        } else {
+            "scrollback"
+        }
+    ));
     details.push(format!("log dir: {}", config.log_dir.display()));
     details.push(format!(
         "sqlite home: {}",

codex-rs/cli/src/doctor/output.rs

@@ -1415,6 +1415,10 @@ Background Server
     #[test]
     fn render_human_report_snapshot_covers_environment_rows() {
         let mut report = sample_report();
+        report.checks.push(
+            DoctorCheck::new("config.load", "config", CheckStatus::Ok, "config loaded")
+                .detail("configured TUI mode: fullscreen"),
+        );
         report.checks.push(DoctorCheck::new(
             "system.disk",
             "disk",

codex-rs/cli/src/doctor/snapshots/codex__doctor__output__tests__doctor_human_report_environment_rows.snap

@@ -45,6 +45,9 @@ Environment
   ✓ state        state paths inspectable
 
 Configuration
+  ✓ config       loaded
+      feature flags            0 enabled · 0 overridden
+      configured TUI mode      fullscreen
   ✗ auth         token expired — Run `codex login`.
       OPENAI_API_KEY           present
 
@@ -69,7 +72,7 @@ Background Server
   ✓ app-server   background server is not running
 
 ─────────────────────────────────────────────────────────────
-15 ok · 5 notes · 3 warn · 1 fail failed
+16 ok · 5 notes · 3 warn · 1 fail failed
 
 --summary compact output           --all expand truncated lists
 --json redacted report

codex-rs/cli/tests/doctor_path_safety.rs

@@ -414,6 +414,24 @@ fn doctor_reports_only_safe_config_error_metadata() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn doctor_reports_configured_tui_mode() -> Result<()> {
+    let fixture = Fixture::new()?;
+    for (setting, expected) in [("true", "fullscreen"), ("false", "scrollback")] {
+        let output = fixture
+            .command()?
+            .args(["-c", &format!("tui.fullscreen_transcript={setting}")])
+            .args(["doctor", "--json"])
+            .output()?;
+        let report: Value = serde_json::from_slice(&output.stdout)?;
+        assert_eq!(
+            report["checks"]["config.load"]["details"]["configured TUI mode"],
+            expected
+        );
+    }
+    Ok(())
+}
+
 #[test]
 fn doctor_reports_configured_filesystem_paths() -> Result<()> {
     let fixture = Fixture::new()?;