## Why
Clients that use full-history resume or request full items in turn pages should
work consistently across legacy and paginated threads.
## What changed
- Materialize complete turns and items from the paginated projection for
`thread/resume` and `thread/turns/list` when requested.
- Support `initialTurnsPage` during paginated resume, including merging a live
active turn while preserving the requested page size and cursors.
- Keep metadata-only resume behavior and backwards cursors available through
`excludeTurns: true`.
## Testing
- Extend app-server coverage for full paginated history, full item views, and
initial resume pages on running threads.
GitOrigin-RevId: e340f44d631ce135895c95d7e1baa7bfecd86e71
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