Add independent controls for TUI visual effects (#46832)

## What changed

Replace `tui.whimsy` with `[tui.effects]` preferences for `starfield`, `shimmer`, `welcome`, `effort`, `progress`, and `title`. Each defaults to `true` and remains subordinate to the `tui.animations` master switch.

Wire the preferences into composer effects, welcome artwork, status and loading text, progress indicators, and terminal-title animations. For example, disable shimmering text while keeping progress animations:

```toml
[tui.effects]
shimmer = false
```

Keep retired `tui.whimsy` entries loadable but ignore their value. Update the configuration schema to expose the new preferences.

## Testing

Add and extend coverage for independent shimmer and progress effects, master-switch precedence, welcome and starfield controls, terminal-title blinking, and strict configuration loading with the retired setting.

GitOrigin-RevId: 28b37ba52872133b8954543cabe9ff424147f1c5

codex-rs/core/config.schema.json

@@ -4210,6 +4210,22 @@
           "description": "When true, disables burst-paste detection for typed input entirely. All characters are inserted as they are received, and no buffering or placeholder replacement will occur for fast keypress bursts. Overrides the legacy top-level `disable_paste_burst` setting. Defaults to `false`.",
           "type": "boolean"
         },
+        "effects": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/TuiEffects"
+            }
+          ],
+          "default": {
+            "effort": true,
+            "progress": true,
+            "shimmer": true,
+            "starfield": true,
+            "title": true,
+            "welcome": true
+          },
+          "description": "Individual visual effects. Each also requires animations to be enabled."
+        },
         "keymap": {
           "allOf": [
             {
@@ -4527,11 +4543,6 @@
           "default": false,
           "description": "Start the composer in Vim mode (`Normal`) by default. Defaults to `false`.",
           "type": "boolean"
-        },
-        "whimsy": {
-          "default": true,
-          "description": "Enable decorative effects such as Astra composer stars. Also requires animations. Defaults to `true`.",
-          "type": "boolean"
         }
       },
       "type": "object"
@@ -4971,6 +4982,43 @@
       },
       "type": "object"
     },
+    "TuiEffects": {
+      "additionalProperties": false,
+      "description": "Optional visual effects. Disabling an effect preserves its underlying activity.",
+      "properties": {
+        "effort": {
+          "default": true,
+          "description": "Animate reasoning-effort changes in the composer and footer.",
+          "type": "boolean"
+        },
+        "progress": {
+          "default": true,
+          "description": "Animate activity bullets and loading spinners.",
+          "type": "boolean"
+        },
+        "shimmer": {
+          "default": true,
+          "description": "Shimmer status and loading text.",
+          "type": "boolean"
+        },
+        "starfield": {
+          "default": true,
+          "description": "Animate the composer starfield.",
+          "type": "boolean"
+        },
+        "title": {
+          "default": true,
+          "description": "Blink the terminal-title indicator when user action is required.",
+          "type": "boolean"
+        },
+        "welcome": {
+          "default": true,
+          "description": "Animate the welcome artwork.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
     "TuiGlobalKeymap": {
       "additionalProperties": false,
       "description": "Global keybindings. These are used when a context does not define an override.",

codex-rs/core/src/config/config_tests.rs

@@ -1253,7 +1253,7 @@ fn config_toml_deserializes_model_availability_nux() {
             notification_settings: TuiNotificationSettings::default(),
             animations: true,
             screen_reader_detection_done: None,
-            whimsy: true,
+            effects: Default::default(),
             show_tooltips: true,
             show_server_version_notice: true,
             auto_recap: true,
@@ -4380,7 +4380,7 @@ fn tui_config_missing_notifications_field_defaults_to_enabled() {
             notification_settings: TuiNotificationSettings::default(),
             animations: true,
             screen_reader_detection_done: None,
-            whimsy: true,
+            effects: Default::default(),
             show_tooltips: true,
             show_server_version_notice: true,
             auto_recap: true,

codex-rs/core/src/config/mod.rs

@@ -748,8 +748,8 @@ pub struct Config {
     /// Enable ASCII animations and shimmer effects in the TUI.
     pub animations: bool,
 
-    /// Enable decorative TUI effects such as Astra composer stars.
-    pub tui_whimsy: bool,
+    /// Individual TUI effects, subordinate to the animation master switch.
+    pub tui_effects: codex_config::types::TuiEffects,
 
     /// Show startup tooltips in the TUI welcome screen.
     pub show_tooltips: bool,
@@ -4382,7 +4382,7 @@ impl Config {
                 .map(|t| t.notification_settings.clone())
                 .unwrap_or_default(),
             animations: cfg.tui.as_ref().map(|t| t.animations).unwrap_or(true),
-            tui_whimsy: cfg.tui.as_ref().map(|t| t.whimsy).unwrap_or(true),
+            tui_effects: cfg.tui.as_ref().map(|t| t.effects).unwrap_or_default(),
             show_tooltips: cfg.tui.as_ref().map(|t| t.show_tooltips).unwrap_or(true),
             tui_show_server_version_notice: cfg
                 .tui