@cloudflare/think@0.8.4

### Patch Changes

-   [#1686](https://github.com/cloudflare/agents/pull/1686) [`1e49880`](https://github.com/cloudflare/agents/commit/1e498803fe26970aa264678d5ae3a2c96dd28258) Thanks [@threepointone](https://github.com/threepointone)! - Batch and pack chat-persistence SQLite writes to reduce rows written and round-trips.
    -   `agents`: `ResumableStream` now **packs** each buffered group of stream chunks into a single SQLite row (a JSON array of chunk bodies) instead of writing one row per chunk. Single-chunk and large-chunk segments are stored unwrapped, and a per-segment byte cap keeps rows within the 2 MB SQLite row limit. This cuts chunk rows written / stored / scanned-on-replay by up to ~10×. Reads (replay, orphan reconstruction, `getStreamChunks`) transparently unpack both packed segments and legacy per-chunk rows, so existing stored data keeps working. Adds shared `buildInClauseStrings` and `MAX_BOUND_PARAMS` helpers exported from `agents/chat`.
    -   `@cloudflare/ai-chat`: message cleanup (stale-row pruning and `maxPersistedMessages` enforcement) previously issued one `DELETE` per row in a loop; it now deletes rows in batched `DELETE ... WHERE id IN (...)` queries (capped at 100 bound parameters per query).
    -   `@cloudflare/think`: `deleteSubmissions()` cleanup previously issued one `DELETE` per terminal submission (up to 500 per call); it now deletes rows in batched `DELETE ... WHERE submission_id IN (...)` queries.
    -   `@cloudflare/ai-chat` & `@cloudflare/think`: chat-recovery incident TTL sweep previously deleted each stale incident with a separate awaited `storage.delete(key)` (which also defeats Durable Object write-coalescing); it now deletes incidents in batched `storage.delete(keys)` calls (up to 128 keys per call).