052: A wire in two languages: the EN/PT switch, kept per wire

Scenario

Given a vault whose wire.languages lists two or more languages
When I open the wire
Then a switch under the lens offers them, the first chosen
When I pick the second
Then every story's headline, summary and why-it-matters are drawn in it where the vault carries them, the first language otherwise
And a quote stays in the language of its source and says which
And the choice is remembered for this wire in this browser, and for no other wire

Outcome

Shipped in v0.12.32: wire/wire.js (the switch, tx() picking <field>_<lang>), the contract on each how page names languages, headline_<lang>, summary_<lang>, why_it_matters_<lang> and quote_lang as optional; the snapshot carries headline_pt and the search indexes it. Checked in test_wire.mjs on the Portugal Wire.