Regulatory Data Sources: add a Japan subsection

[eoylab]

Regulatory Data Sources covers the United States and Europe. This adds Japan — specifically administrative enforcement, which is what advertising review and marketing-claim sign-off are checked against in that market.

• keihyo-cases — Consumer Affairs Agency orders under 景品表示法 (the Act against Unjustifiable Premiums and Misleading Representations): 措置命令 and 課徴金納付命令, with the provisions cited in each order.
• jftc-actions — Japan Fair Trade Commission cease-and-desist orders under the Antimonopoly Act, and Subcontract Act (取適法, formerly 下請法) recommendations.

Both are free and open: JSON / JSONL / CSV downloads, an MCP server each on the official MCP Registry, data under the Public Data License 1.0 and code MIT. No account, no key, no rate limit.

Three properties I put in the entry text because they change how the data can be used:

• a source URL on every record — any field traces back to the agency page it came from
• no judgement of their own — each record restates an order already issued and published; nothing is inferred, scored or predicted
• no natural person names in the structured fields; announcements that could not be parsed are kept in a separate file rather than filled in by guesswork

Each site also carries the statement required by the licence that the dataset is not created or published by the agency.

Happy to fold this into the existing lists instead of a subsection, or trim to one line, if that suits the structure better.