fix(PROD-2277): models-only sync crashes in push with ENOENT on galleries folder

[5PK]

Summary

A models-only sync — sync --models="X" (and the same code path for --elements="Models") — crashes in the push phase on a clean machine:

✗ Sync completed with errors
  •  sync: guid-orchestration: ENOENT: no such file or directory,
     scandir 'agility-files/<sourceGuid>/galleries'

This is a regression from PROD-2215 (#166). That fix correctly makes a models-only scope download only model definitions (skipping assets, galleries, content) — but the push-side loader still reads the galleries folder unconditionally, and that folder is now never created.

Root cause

• guid-data-loader.ts (~L85, ~L400) calls getGalleriesFromFileSystem() unconditionally during push.
• → get-galleries.ts → fileOperations.getFolderContents() → fs.readdirSync(folder) with no existence guard (fileOperations.ts ~L273).
• Pre-PROD-2215 the downloader fetched galleries regardless of scope, which created agility-files/<guid>/galleries (even empty), so readdirSync returned []. PROD-2215 stopped creating it for models-only runs → ENOENT.

Fix

getFolderContents now creates the folder on demand and returns [] when absent, matching the guards already in readJsonFilesFromFolder/listFilesInFolder:

getFolderContents(folder: string) {
  if (!fs.existsSync(folder)) {
    fs.mkdirSync(folder, { recursive: true });
    return [];
  }
  return fs.readdirSync(folder);
}

Creating the folder (rather than only guarding the read) also restores the consistent instance-folder scaffolding downstream steps assume. All four callers (get-galleries, gallery-mapper, mapping-reader ×2) want "list files, empty if none", so auto-create is safe.

Testing

• Clean sync --sourceGuid=… --targetGuid=… --models="AssetTest" (no local agility-files, no workaround) → ✓ Sync completed successfully; galleries/assets correctly skipped in push; folders auto-created.
• Regression test added in fileOperations.test.ts (missing folder → returns [] and folder is created).
• Affected suites green (fileOperations / gallery-pusher / gallery-mapper / mapping-reader); full suite 1685 tests passing.

Jira: PROD-2277

🤖 Generated with Claude Code