fix(server): preserve provider usage in persisted turns

Merge terminal provider updates with stored context usage before replacing the SQLite payload. Keep newer usage reports authoritative and verify the persisted projection after reload.

Finding: R07 follow-up

Model: GPT-5.6 Sol via Codex
d81a2f0556Julius Marminge committed on 9/5/2026, 4:54:28 AMparent22acb61
2 files changedLine totals unavailable