Function fetchRootLevelFallbackSkill

src/lib/sources.ts:519–602

* Fallback path used when an explicit single-skill source points at a flat skill * with root-level files. Fetches and writes that skill into `fetchedSkills`. * Returns whether the fallback fired and the resulting remote skill names.

(params: {
  entries: GitHubFileEntry[];
  parsed: ParsedSource;
  ref: string;
  resolvedSha: string;
  skillFilter: string[];
  isWildcard: boolean;
  curatedDir: string;
  locked: LockedSource | undefined;
  sourceKey: string;
  localSkillNames: Set<string>;
  alreadyFetchedSkillNames: Set<string>;
  client: GitHubClient;
  semaphore: Semaphore;
  fetchedSkills: Record<string, LockedSkill>;
  logger: Logger;
})

 * Returns whether the fallback fired and the resulting remote skill names.
 */
async function fetchRootLevelFallbackSkill(params: {
  entries: GitHubFileEntry[];
  parsed: ParsedSource;
  ref: string;
  resolvedSha: string;
  skillFilter: string[];
  isWildcard: boolean;
  curatedDir: string;
  locked: LockedSource | undefined;
  sourceKey: string;
  localSkillNames: Set<string>;
  alreadyFetchedSkillNames: Set<string>;
  client: GitHubClient;
  semaphore: Semaphore;
  fetchedSkills: Record<string, LockedSkill>;
  logger: Logger;
}): Promise<{ handled: boolean; remoteSkillNames: string[] }> {
  const {
    entries,
    parsed,
    ref,
    resolvedSha,
    skillFilter,
    isWildcard,
    curatedDir,
    locked,
    sourceKey,
    localSkillNames,
    alreadyFetchedSkillNames,
    client,
    semaphore,
    fetchedSkills,
    logger,
  } = params;

  const rootFiles = entries.filter((entry) => entry.type === "file");
  const rootSkillFiles: RemoteSkillFile[] = [];

  for (const file of rootFiles) {
    if (file.size > MAX_FILE_SIZE) {
      logger.warn(
        `Skipping file "${file.path}" (${(file.size / 1024 / 1024).toFixed(2)}MB exceeds ${MAX_FILE_SIZE / 1024 / 1024}MB limit).`,
      );
      continue;
    }
    const content = await withSemaphore(semaphore, () =>
      client.getFileContent(parsed.owner, parsed.repo, file.path, ref),
    );
    rootSkillFiles.push({ relativePath: file.name, content });
  }

  const groupedRootFiles = groupRemoteFilesBySkillRoot({
    remoteFiles: rootSkillFiles,
    skillFilter,
    isWildcard,
  });
  const [fallbackSkillName] = groupedRootFiles.keys();
  if (fallbackSkillName === undefined) {