chore: import upstream snapshot with attribution

showcase/integrations/claude-sdk-python/qa/voice.md

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+# QA: Voice input — Claude Agent SDK (Python)
+
+## Prerequisites
+
+- Demo is deployed and accessible
+- Agent backend is healthy (check /api/health)
+- `ANTHROPIC_API_KEY` is set on the deployment (for chat replies)
+- `OPENAI_API_KEY` is set on the Next.js runtime (for Whisper
+  transcription). If it is not, the mic button still renders but
+  clicking it (or clicking "Play sample") will return a clean 401.
+
+## Test Steps
+
+### 1. Basic Functionality
+
+- [ ] Navigate to `/demos/voice`
+- [ ] Verify the "Voice input" header renders
+- [ ] Verify the mic button is visible on the chat composer
+- [ ] Verify the "Play sample" button renders next to a caption
+      matching `SAMPLE_LABEL` (e.g. "What is the weather in Tokyo?")
+
+### 2. Feature-Specific Checks
+
+#### Play sample
+
+- [ ] Click "Play sample"
+- [ ] Verify the button flips to "Transcribing…" briefly
+- [ ] Verify the composer's textarea is populated with the transcribed
+      text
+- [ ] Press send and verify Claude replies to the transcribed prompt
+
+#### Mic button (manual)
+
+- [ ] Click the mic button, allow microphone access, speak a short
+      sentence, click again
+- [ ] Verify the textarea is populated with the transcription
+- [ ] Press send and verify Claude replies
+
+### 3. Misconfigured deployment
+
+- [ ] With `OPENAI_API_KEY` unset, click "Play sample"
+- [ ] Verify the error slot renders "Error — see console"
+- [ ] Verify the network response is HTTP 401, not 500/503
+
+### 4. Error Handling
+
+- [ ] No console errors during normal usage (other than the expected
+      401 when `OPENAI_API_KEY` is missing).
+
+## Expected Results
+
+- Mic button always visible (transcription service is always mounted).
+- Missing `OPENAI_API_KEY` manifests as 401, not silent failure.