feat(demos): add affinity testing demo for model pinning

crates/brightstaff/src/router/http.rs

@@ -1,5 +1,5 @@
+use hermesllm::apis::openai::ChatCompletionsResponse;
 use hyper::header;
-use serde::Deserialize;
 use thiserror::Error;
 use tracing::warn;
 
@@ -12,23 +12,8 @@ pub enum HttpError {
     Json(serde_json::Error, String),
 }
 
-#[derive(Debug, Deserialize)]
-struct RouterChatCompletionResponse {
-    choices: Vec<RouterChoice>,
-}
-
-#[derive(Debug, Deserialize)]
-struct RouterChoice {
-    message: RouterMessage,
-}
-
-#[derive(Debug, Deserialize)]
-struct RouterMessage {
-    content: Option<String>,
-}
-
 /// Sends a POST request to the given URL and extracts the text content
-/// from the first choice of a chat-completions-like response.
+/// from the first choice of the `ChatCompletionsResponse`.
 ///
 /// Returns `Some((content, elapsed))` on success, or `None` if the response
 /// had no choices or the first choice had no content.
@@ -45,7 +30,7 @@ pub async fn post_and_extract_content(
     let body = res.text().await?;
     let elapsed = start_time.elapsed();
 
-    let response: RouterChatCompletionResponse = serde_json::from_str(&body).map_err(|err| {
+    let response: ChatCompletionsResponse = serde_json::from_str(&body).map_err(|err| {
         warn!(error = %err, body = %body, "failed to parse json response");
         HttpError::Json(err, format!("Failed to parse JSON: {}", body))
     })?;