## What changed
- Add the experimental `thread/searchOccurrences` app-server method for case-insensitive literal search across visible user messages and final assistant messages without replaying the thread.
- Return paginated snippets with UTF-16 match ranges and `thread/turns/list` cursors for navigating to each matching turn.
- Index persisted item types to efficiently select searchable messages from paginated thread history.
## Testing
- Add an app-server integration test covering pagination, steering messages, final-answer selection, Markdown normalization, and UTF-16 offsets.
GitOrigin-RevId: e80160e0f83eb4e5db8de862307085093bee362b
## What changed
- Project durable paginated rollout records into rebuildable SQLite tables for turns, items, and projection progress while keeping JSONL as the source of truth.
- Add cursor-based local reads for turn summaries and thread or per-turn items, including archived-thread and history-mode validation.
- Serialize writes, shutdown, and deletion per thread so projection updates cannot race cleanup, and remove projected rows when a thread is deleted.
- Preserve stable item ordering while updating repeated snapshots and expose structured turn error details.
## Testing
- Cover projection, snapshot updates, summary recovery, pagination, failure handling, shutdown flushing, legacy-mode rejection, and deletion races.
GitOrigin-RevId: 34533185ece7f1f5690004c7f12b0f1f34dc2640
## Why
Paginated thread history needs its own SQLite database to avoid adding lock
contention to the main state store.
## What changed
- Add the `thread_history_1.sqlite` path and migration scaffolding.
- Create tables and pagination indexes for projected turns and items, plus a
per-thread projection checkpoint.
- Register the database with runtime diagnostics, Bazel inputs, and database
telemetry.
GitOrigin-RevId: d194310835f1df2a2a29c7827d77ca37eabbd0a3
