chore: initialize autoresearch baseline

crates/api-contracts/src/error.rs

@@ -0,0 +1,38 @@
+use serde::Serialize;
+
+#[derive(Debug, Clone, Serialize)]
+pub struct ErrorResponse {
+    pub error: ApiError,
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct ApiError {
+    pub message: String,
+    #[serde(rename = "type")]
+    pub error_type: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub param: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub code: Option<String>,
+}
+
+impl ApiError {
+    pub fn new(message: impl Into<String>, error_type: impl Into<String>) -> Self {
+        Self {
+            message: message.into(),
+            error_type: error_type.into(),
+            param: None,
+            code: None,
+        }
+    }
+
+    pub fn with_code(mut self, code: impl Into<String>) -> Self {
+        self.code = Some(code.into());
+        self
+    }
+
+    pub fn with_param(mut self, param: impl Into<String>) -> Self {
+        self.param = Some(param.into());
+        self
+    }
+}