Add metadata.upstream: tinystruct==1.7.34 to both the English skill and
its Japanese translation, so a future sync can mechanically diff the
pinned version against the current tinystruct release instead of
rediscovering drift from prose. Also migrates the legacy top-level
`origin: ECC` key into the metadata block, matching the schema used by
the rest of the skills in this repo (tests/commands/learn-skill-discovery.test.js
already asserts top-level `origin:` is unsupported).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>