fix(mindspace): map publication RPC errors to HTTP status codes

Return 404/401/403 from MindSpace RPC for known publication errors and
preserve error codes through the Portal remote adapter.

Co-authored-by: Cursor <cursoragent@cursor.com>

mindspace-remote-server-adapter.mjs

@@ -27,17 +27,32 @@ function buildRemoteOperationUrl(endpoint, bindingKey, method, operationBasePath
   return `${base}${normalizedBasePath}/${encodeURIComponent(bindingKey)}/${encodeURIComponent(method)}`;
 }
 
-async function parseRemoteOperationResponse(response, bindingKey, method) {
-  if (!response.ok) {
-    const bodyText = await response.text().catch(() => '');
-    throw new Error(
+function throwRemoteOperationError(response, bindingKey, method, bodyText, payload) {
+  const error = new Error(
+    payload?.message ??
       `MindSpace remote adapter ${bindingKey}.${method}() failed with ${response.status}${bodyText ? `: ${bodyText}` : ''}`,
-    );
+  );
+  if (payload?.code) error.code = payload.code;
+  if (payload?.details !== undefined) error.details = payload.details;
+  throw error;
+}
+
+async function parseRemoteOperationResponse(response, bindingKey, method) {
+  const bodyText = await response.text().catch(() => '');
+  let payload = null;
+  if (bodyText) {
+    try {
+      payload = JSON.parse(bodyText);
+    } catch {
+      payload = null;
+    }
+  }
+  if (!response.ok) {
+    throwRemoteOperationError(response, bindingKey, method, bodyText, payload);
   }
   if (response.status === 204) return null;
-  const text = await response.text();
-  if (!text) return null;
-  return JSON.parse(text);
+  if (!bodyText) return null;
+  return payload ?? JSON.parse(bodyText);
 }
 
 async function invokeRemoteOperation({