message: nicer error for missing parent card
diff: @@ -132,13 +132,16 @@ export class Compiler {
  private async getParentCard(cardSource: RawCard, meta: PluginMeta): Promise<CompiledCard> {
  let parentCardPath = this.getCardParentPath(cardSource, meta);
  -
  - if (parentCardPath) {
  - let url = new URL(parentCardPath, cardSource.url).href;
  + let url = parentCardPath ? new URL(parentCardPath, cardSource.url).href : baseCardURL;
  + try {
  return await this.builder.getCompiledCard(url);
  - } else {
  - // the base card from which all other cards derive
  - return await this.builder.getCompiledCard(baseCardURL);
  + } catch (err: any) {
  + if (!err.isCardstackError || err.status !== 404) {
  + throw err;
  + }
  + let newErr = new CardstackError(`tried to adopt from card ${url} but it failed to load`, { status: 422 });
  + newErr.additionalErrors = [err, ...(err.additionalErrors || [])];
  + throw newErr;
  }
  }
  