Add a Typesense provider layer

[TitusKirch]

Before you start

• I searched existing issues and didn't find a duplicate

What problem are you trying to solve?

duxt will expose normalized, build-time search records through #16. A site that already runs Typesense needs an official way to consume those records without recreating duxt's source, version, locale, and generated-section logic.

The built-in search decision in #33 must remain independent: Typesense is an opt-in provider for consumers that choose to operate or buy the service.

Proposed solution

Provide a Typesense provider layer that consumes duxt:search:records after #16 lands.

It should let a consumer synchronize the complete current record set to a Typesense collection during its build, with stable record identity and removal of records no longer present in a later build. Searchable content and filterable provenance must preserve the common contract: URL, title, normalized plaintext, source, version, and locale.

The provider layer owns its credentials, service configuration, synchronization policy, and browser search integration. duxt itself gains no Typesense SDK, runtime hook, or service dependency.

Alternatives considered

• Make Typesense the duxt default: rejected because every consumer would have to operate or pay for an external service.
• Build a separate crawler or scraper: rejected because Decide the extension surface: hooks, plugins, or neither #16 already provides the normalized records.
• Include the adapter in Evaluate one search index across all sources #33: rejected because Evaluate one search index across all sources #33 decides only the built-in Pagefind default.

Additional context

• Depends on Decide the extension surface: hooks, plugins, or neither #16 landing duxt:search:records.
• Evaluate one search index across all sources #33 evaluates Pagefind as the built-in consumer of the same records.
• The provider must work for records from every source, version, locale, and generated section.

Decided (refinement pass, 2026-09-11):

• The official provider ships as the independently published companion Nuxt layer @kirchdev/duxt-typesense, in its own repository. It consumes the public hook but is not a workspace package or optional export of @kirchdev/duxt.
• Add a Typesense provider layer #74 remains blocked by Decide the extension surface: hooks, plugins, or neither #16. Implementation begins only once duxt:search:records has landed; GitHub records this as a native “blocked by Decide the extension surface: hooks, plugins, or neither #16” dependency.
• @kirchdev/duxt remains free of the Typesense SDK, credentials, runtime hooks, and service configuration. Those are exclusively the companion layer’s responsibility.