user_medal_args was declared as type=json without sanitize_type, so
sanitize_field_value() fell through to sanitize_text_field((string) $value)
and stored the literal string "Array". validate() has no json shape check,
so the save reported success.
Consequence: parse_medal_catalog() json_decoded "Array" into an empty
catalog, the dictionary came back empty, and user_context() dropped every
owned badge — the front end showed "获取徽章" and the grant modal listed
nothing, hiding both the newly added and the pre-existing badges.
Add the missing sanitize_type to match its sibling level/integral fields,
and guard sanitize_field_value() so structured container types can never
reach the scalar fallback again. Mirrors the declaration in the Vue schema.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
