app.tempomusic.feed.getTimeline

Paginated chronological feed of timeline items. Each item is discriminated by `$type` (today only `app.tempomusic.feed.post`; future variants such as `app.tempomusic.feed.review` plug in additively). When the request carries a service-auth JWT, the viewer DID is read from its `iss` claim and each returned item carries a viewer projection; anonymous requests receive items without viewer state.