feat: add chat completions route + test

src/routes/v1/models.rs

@@ -30,8 +30,27 @@ pub async fn completions(
             axum::http::StatusCode::UNPROCESSABLE_ENTITY,
             format!("model '{m}' is not available — run `ollama pull {m}` first"),
         )),
+        Err(e) => Err((axum::http::StatusCode::INTERNAL_SERVER_ERROR, e.to_string())),
+    }
+}
+
+pub async fn chat_completions(
+    State(state): State<AppState>,
+    Json(body): Json<Value>,
+) -> Result<Json<Value>, (axum::http::StatusCode, String)> {
+    match state.ollama.chat_completions(body).await {
+        Ok(response) => Ok(Json(response)),
+        Err(OllamaError::MissingMessages) => Err((
+            axum::http::StatusCode::BAD_REQUEST,
+            "messages must be a non-empty array with at least one user message".to_string(),
+        )),
+        Err(OllamaError::ModelNotFound(m)) => Err((
+            axum::http::StatusCode::UNPROCESSABLE_ENTITY,
+            format!("model '{m}' is not available — run `ollama pull {m}` first"),
+        )),
         Err(OllamaError::Http(e)) => {
             Err((axum::http::StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))
         }
+        Err(e) => Err((axum::http::StatusCode::BAD_REQUEST, e.to_string())),
     }
 }