Fix Export Folder Zipper metadata and app index

[RodneyBaker]

@shun-iwasawa
This follow-up fixes the Export Folder Zipper listing after merge.

Changes:

• Replaces meta.json with valid UTF-8 JSON without BOM.
• Keeps manual line breaks escaped as \n so the metadata parser can read the file.
• Regenerates ai_tools/apps/apps-index.js so export_folder_zipper appears in the OPAT menu/listing.

For your consideration.

[shun-iwasawa]

LGTM