Add application translation intent type

[drinkbeer]

Proposal

Add application/translation with create and edit actions for merchant-facing localized content.

This unblocks requests such as:

• Translate product descriptions into French.
• Review Spanish store translations.
• Update the German translation of a shipping policy.

The optional schema fields carry the translated artifact and routing context: app-specific translation ID, resource ID/type/key, source and target locales, source and translated content, and an optional Market ID. It intentionally declares no required fields so Sidekick can route broad translation requests and collect missing context in the app.

Companion work

• Core registration and canonical schema: shop/world#946585
• CDN schema publication: Shopify/extensibility#1569
• First app integration: Shopify/store-localization#6257

The real Sidekick tophat remains blocked until the Core registration deploys and the canonical CDN URL is published.

[drinkbeer]

We changed the hackday plan to reuse the existing application/email intent for a local-only plumbing tophat. We are no longer proposing or deploying a new translation intent as part of this work, so I am closing this proposal. Thanks for the guidance.