feat(tui) /personality (#9718)

## Summary
Adds /personality selector in the TUI, which leverages the new core
interface in #9644

Notes:
- We are doing some of our own state management for model_info loading
here, but not sure if that's ideal. open to opinions on simpler
approach, but would like to avoid blocking on a larger refactor
- Right now, the `/personality` selector just hides when the model
doesn't support it. we can update this behavior down the line

## Testing
- [x] Tested locally
- [x] Added snapshot tests

codex-rs/protocol/src/config_types.rs

@@ -2,6 +2,7 @@ use schemars::JsonSchema;
 use serde::Deserialize;
 use serde::Serialize;
 use strum_macros::Display;
+use strum_macros::EnumIter;
 use ts_rs::TS;
 
 use crate::openai_models::ReasoningEffort;
@@ -78,6 +79,7 @@ pub enum SandboxMode {
     TS,
     PartialOrd,
     Ord,
+    EnumIter,
 )]
 #[serde(rename_all = "lowercase")]
 #[strum(serialize_all = "lowercase")]

codex-rs/protocol/src/openai_models.rs

@@ -78,6 +78,9 @@ pub struct ModelPreset {
     pub default_reasoning_effort: ReasoningEffort,
     /// Supported reasoning effort options.
     pub supported_reasoning_efforts: Vec<ReasoningEffortPreset>,
+    /// Whether this model supports personality-specific instructions.
+    #[serde(default)]
+    pub supports_personality: bool,
     /// Whether this is the default model for new users.
     pub is_default: bool,
     /// recommended upgrade model
@@ -214,6 +217,12 @@ impl ModelInfo {
         })
     }
 
+    pub fn supports_personality(&self) -> bool {
+        self.model_instructions_template
+            .as_ref()
+            .is_some_and(ModelInstructionsTemplate::supports_personality)
+    }
+
     pub fn get_model_instructions(&self, personality: Option<Personality>) -> String {
         if let Some(personality) = personality
             && let Some(template) = &self.model_instructions_template
@@ -249,6 +258,13 @@ impl ModelInstructionsTemplate {
     fn has_personality_placeholder(&self) -> bool {
         self.template.contains(PERSONALITY_PLACEHOLDER)
     }
+
+    fn supports_personality(&self) -> bool {
+        self.has_personality_placeholder()
+            && self.personality_messages.as_ref().is_some_and(|messages| {
+                Personality::iter().all(|personality| messages.0.contains_key(&personality))
+            })
+    }
 }
 
 // serializes as a dictionary from personality to message
@@ -280,6 +296,7 @@ pub struct ModelsResponse {
 // convert ModelInfo to ModelPreset
 impl From<ModelInfo> for ModelPreset {
     fn from(info: ModelInfo) -> Self {
+        let supports_personality = info.supports_personality();
         ModelPreset {
             id: info.slug.clone(),
             model: info.slug.clone(),
@@ -289,6 +306,7 @@ impl From<ModelInfo> for ModelPreset {
                 .default_reasoning_level
                 .unwrap_or(ReasoningEffort::None),
             supported_reasoning_efforts: info.supported_reasoning_levels.clone(),
+            supports_personality,
             is_default: false, // default is the highest priority available model
             upgrade: info.upgrade.as_ref().map(|upgrade| ModelUpgrade {
                 id: upgrade.model.clone(),