[实时转写]：完成录音期间转写显示，包含partial事件、本地streaming STT和终端实时反馈

openspec/changes/separate-wake-and-realtime-transcript/design.md

@@ -111,6 +111,16 @@ The first implementation is a per-turn heuristic endpoint, not persistent voicep
 4. 主说话人画像就绪后，`OWNER_SPEAKER_ABSENT_MS` 是结束正式问题采集的主条件；主说话人连续缺席达到该值后直接进入 STT，不再额外等待普通 VAD 最小时长。
 5. 普通 VAD 静音仍作为画像不足或音色特征不可用时的兜底，最大录音时长仍作为最终保护。
 
+## Realtime Transcript Revision
+
+录音期间新增 partial transcript 通道，用于解决“说话时看不到文字结果”的体验问题：
+
+1. Pipeline 事件新增 `transcript_partial`。终端 reporter 将其显示为 `实时转写：<文本>`，最终结果仍显示为 `转写结果：<文本>`。
+2. partial transcript 只用于用户反馈，不写入 `ConversationContext`，不触发 LLM；LLM 仍只消费 final STT 结果。
+3. 当 final ASR/TTS 走 cloud 时，partial transcript 使用本地 `sherpa-onnx` streaming STT，避免对云端 ASR 高频请求。
+4. `VoiceAssistantPipeline` 在 `speech_started` 后把 capture 阶段已开始录音的帧 feed 给 realtime STT session；当 partial 文本变化时才 emit，避免刷屏。
+5. `OWNER_REALTIME_TRANSCRIPT_ENABLED=1` 默认启用；设置为 `0` 可临时回退到只显示 final transcript。
+
 ## Model Files
 
 ```text
@@ -141,6 +151,7 @@ models/
 8. Pipeline stage failure: emit `stage_error`, recover to standby, and keep the process alive unless startup dependencies are missing.
 9. Playback drain misconfiguration: negative `OWNER_POST_PLAYBACK_DRAIN_MS` remains invalid; non-zero values are treated as explicit user tuning rather than default behavior.
 10. Speaker profile threshold misconfiguration: non-positive `OWNER_SPEAKER_PROFILE_MIN_MS` fails config validation.
+11. Realtime STT failure: startup model缺失按 `model-check` 暴露；capture 中 partial session 失败不得把 partial 文本写入上下文。
 
 ## Testing Strategy
 
@@ -155,6 +166,8 @@ models/
 9. First utterance preservation test validates that frames immediately after ACK are not discarded by post-playback drain.
 10. Low-latency endpoint test validates that a short first question ends by primary speaker absence without waiting for a repeated second question.
 11. Transport batching test validates that queued SoundDevice frames are returned together.
+12. Partial transcript event test validates that realtime text appears after speech start and before final transcript.
+13. Context isolation test validates partial transcript does not enter LLM messages.
 
 ## Migration