[chodorowicz]

Description

Add custom vizualation's schema.

Depends on Gdgt 2618 add custom viz to the representation format schema by chodorowicz · Pull Request #84530 · metabase/metabase which needs to be merged first.

Chosen option:

Unpacked archive (unpack on export, pack on import)

• ✅ the manifest and icon become reviewable; name, version ranges and icon are visible
  without extracting anything
• ✅ inline with how data apps are exported
• 🟠 the JS is minified with libs bundled in, so the code itself is still not reviewable
• ⛔ most complex flow: export unpacks, import must repack; the repacked archive differs
  byte-for-byte from the upload, so the stored bundle hash doesn't round-trip

Other options considered

tar stored inline

• ✅ minimal change, no new serdes concepts
• ✅ one file per plugin, nothing can drift (manifest, code and icon travel together)
• ⛔ large YAML files (a bundle with vendored libs is easily hundreds of KB of base64)
• ⛔ not reviewable in the exported format; every rebuild is a full-file diff

Bundle as a separate bundle.tgz next to the YAML

• ✅ clean split of binary from text; YAML stays small and fast to parse
• ✅ git handles the archive as a binary blob instead of a huge text diff
• ⛔ serdes has no notion of byte resources yet (file writer, git snapshot reader, tar
  writer all assume text), so this needs new plumbing in the serialization layer
• ⛔ two files that must stay in sync

[linear]

GDGT-2618