v0.216.4

[0.216.4] - 2026-09-04

Release summary: 2 bug fixes, 1 refactor, and 1 docs update.
Tag range: v0.216.3..v0.216.4.

Bug Fixes

• dreaming: stop retaining backlog text
• dreaming: make backlog probes threshold-aware

Refactoring

• dreaming: simplify backlog probes

Docs

• readme: add missing contributors (#1846)