perf: fix memory leaks, optimize tracing logs, fix networking eof fragmentation bug in nvim-core and stub, and deduplicate json-rpc handlers

server/src/error.rs

@@ -0,0 +1,39 @@
+use axum::{
+    http::StatusCode,
+    response::{IntoResponse, Response},
+    Json,
+};
+use serde_json::json;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum AppError {
+    #[error("Not Found: {0}")]
+    NotFound(String),
+
+    #[error("Forbidden: {0}")]
+    Forbidden(String),
+
+    #[error("Internal Server Error: {0}")]
+    Internal(String),
+
+    #[error("Bad Request: {0}")]
+    BadRequest(String),
+}
+
+impl IntoResponse for AppError {
+    fn into_response(self) -> Response {
+        let (status, error_message) = match &self {
+            AppError::NotFound(msg) => (StatusCode::NOT_FOUND, msg.clone()),
+            AppError::Forbidden(msg) => (StatusCode::FORBIDDEN, msg.clone()),
+            AppError::Internal(msg) => (StatusCode::INTERNAL_SERVER_ERROR, msg.clone()),
+            AppError::BadRequest(msg) => (StatusCode::BAD_REQUEST, msg.clone()),
+        };
+
+        let body = Json(json!({
+            "error": error_message,
+        }));
+
+        (status, body).into_response()
+    }
+}