load models from disk and set a ttl and etag (#7722)

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codex-rs/protocol/src/openai_models.rs

@@ -141,6 +141,8 @@ pub struct ModelInfo {
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq, TS, JsonSchema, Default)]
 pub struct ModelsResponse {
     pub models: Vec<ModelInfo>,
+    #[serde(default)]
+    pub etag: String,
 }
 
 fn default_visibility() -> ModelVisibility {