Revert "fix: ensure stop_reason is always set and reduce noisy logs (#9046)"
This reverts commit 4241a360579440d2697124ba69061d0e46ecc5e9.
**Problem:**
After the original change, caren-code-agent reported streams hanging
indefinitely. The trace shows ttft (time to first token) succeeds, but
the stream never closes.
**Root Cause (suspected):**
The change modified `is_complete=is_done` to `is_complete=saw_done`,
meaning error events no longer mark the stream as complete immediately.
This may cause timing issues where clients wait for more data before
the finalizer runs.
**Fix:**
Revert to the defensive "belt-and-suspenders" approach that always
appends [DONE]. The noisy logs are preferable to hanging streams.
The original comment noted: "Even if a previous chunk set `complete`,
an extra [DONE] is harmless and ensures SDKs that rely on explicit
[DONE] will exit."
👾 Generated with [Letta Code](https://letta.com)
Co-authored-by: Letta <noreply@letta.com>
2bccd36382