feat: bootstrap awg2 harness rust workspace and docs

traffic_core/src/error.rs

@@ -0,0 +1,10 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum AppError {
+    #[error("command failed: {0}")]
+    Command(String),
+    #[error("not found: {0}")]
+    NotFound(String),
+}
+