docs: archive changelog for v0.6.20

CHANGELOG.md

@@ -3,6 +3,18 @@
 Published user-facing notes for GitHub Releases and the console update page.
 Write upcoming notes as bilingual files in `changelog/unreleased/`.
 
+## 0.6.20 - 2026-10-09
+
+### English
+
+- Fix Qoder chat silently returning an empty, spec-invalid completion when the upstream gateway answers 200 with heartbeat frames only. The in-process client now rejects the empty stream before relaying (so the executor can cool the account down and fail over), salvages streams that were cut before the terminal `finish_reason` with a synthesized `stop` / `tool_calls` terminal chunk, and rejects empty non-stream responses instead of fabricating `stop`. Strict OpenAI-compatible clients no longer fail with `Stream ended without finish_reason`.
+- Make Qoder quota refresh failures visible to the account refresh endpoint while keeping account readiness intact, and run quota and model catalog refreshes independently.
+
+### 中文
+
+- 修复 Qoder 上游网关偶发 200 + 仅心跳帧时，网关静默返回"空且不合规"的补全。进程内直连客户端现在会在转发前拒绝空流（执行层可冷却该账号并切换到其他账号重试）；对已输出内容但在终态 `finish_reason` 前被切断的流，合成 `stop` / `tool_calls` 终态帧进行挽救；非流式空响应不再凭空合成 `stop` 而是报错。严格的 OpenAI 兼容客户端（如 pi coding agent）不再出现 `Stream ended without finish_reason`。
+- 让 Qoder 额度刷新失败在账号刷新接口中可见，同时保持账号就绪状态不受影响，并让额度与模型目录刷新相互独立执行。
+
 ## 0.6.19 - 2026-10-07
 
 ### English