chore: import upstream snapshot with attribution

examples/provider-elevenlabs/alignment/README.md

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+# provider-elevenlabs/alignment (ElevenLabs Forced Alignment)
+
+Generate time-aligned subtitles (SRT/VTT) from audio and transcripts using ElevenLabs forced alignment.
+
+## Quick Start
+
+```bash
+npx promptfoo@latest init --example provider-elevenlabs/alignment
+cd provider-elevenlabs/alignment
+export ELEVENLABS_API_KEY=your_api_key_here
+npx promptfoo@latest eval
+```
+
+## What this tests
+
+- **Subtitle generation**: Create SRT and VTT subtitle files
+- **Word-level alignment**: Precise timestamp data for each word
+- **Multiple formats**: JSON (raw data), SRT (video players), VTT (web players)
+- **Accuracy**: Verify alignment matches audio timing
+
+## How it works
+
+Forced alignment takes two inputs:
+
+1. **Audio file**: Speech recording (MP3, WAV, etc.)
+2. **Transcript**: Text of what was spoken
+
+It returns precise timestamps showing when each word was spoken, formatted as subtitles.
+
+## Use Cases
+
+- **Video subtitles**: Generate SRT files for video editing software
+- **Web captions**: Create VTT files for HTML5 video players
+- **Karaoke apps**: Word-level timing for synchronized highlighting
+- **Accessibility**: Auto-generate captions for spoken content
+- **Translation sync**: Time-align translations to original audio
+
+## Output Formats
+
+### JSON (Raw alignment data)
+
+```json
+{
+  "alignment": [
+    { "char": "T", "start": 0.0, "end": 0.1 },
+    { "char": "h", "start": 0.1, "end": 0.15 }
+  ],
+  "characters": "That's one small step..."
+}
+```
+
+### SRT (Standard video subtitles)
+
+```text
+1
+00:00:00,000 --> 00:00:02,500
+That's one small step for man
+
+2
+00:00:02,500 --> 00:00:05,000
+one giant leap for mankind
+```
+
+### VTT (WebVTT for web players)
+
+```text
+WEBVTT
+
+1
+00:00:00.000 --> 00:00:02.500
+That's one small step for man
+
+2
+00:00:02.500 --> 00:00:05.000
+one giant leap for mankind
+```
+
+## Configuration
+
+### Basic alignment (JSON output)
+
+```yaml
+providers:
+  - id: elevenlabs:alignment:json
+    label: Alignment (JSON)
+
+tests:
+  - vars:
+      audioFile: path/to/audio.mp3
+      transcript: 'Your transcript text here'
+      format: json
+```
+
+### SRT subtitles
+
+```yaml
+providers:
+  - id: elevenlabs:alignment:srt
+    label: Alignment (SRT Subtitles)
+
+tests:
+  - vars:
+      audioFile: path/to/audio.mp3
+      transcript: 'Your transcript text here'
+      format: srt
+```
+
+### VTT subtitles
+
+```yaml
+providers:
+  - id: elevenlabs:alignment:vtt
+    label: Alignment (VTT Subtitles)
+
+tests:
+  - vars:
+      audioFile: path/to/audio.mp3
+      transcript: 'Your transcript text here'
+      format: vtt
+```
+
+## Testing Assertions
+
+```yaml
+tests:
+  # Verify alignment succeeds
+  - assert:
+      - type: javascript
+        value: output.includes('words') # JSON format
+      - type: not-contains
+        value: error
+
+  # Verify SRT format
+  - assert:
+      - type: javascript
+        value: output.includes('-->') && output.includes('small step')
+```
+
+## Best Practices
+
+1. **Transcript accuracy**: Ensure transcript exactly matches spoken audio
+2. **Include punctuation**: Better subtitle chunking and timing
+3. **Audio quality**: Clear audio produces more accurate timestamps
+4. **Format selection**:
+   - Use SRT for video editing (Premiere, Final Cut, DaVinci)
+   - Use VTT for web players (HTML5 `<video>` tag)
+   - Use JSON for custom processing
+
+## Cost Information
+
+Forced alignment pricing is based on audio duration:
+
+- ~$0.05 per minute of audio
+
+The provider automatically tracks costs in evaluation results.
+
+## Related Examples
+
+- [ElevenLabs STT](../stt/) - Speech-to-text transcription
+- [ElevenLabs Isolation](../isolation/) - Audio noise removal
+
+## Resources
+
+- [ElevenLabs Alignment API Docs](https://elevenlabs.io/docs/api-reference/alignment)
+- [SRT Format Specification](https://en.wikipedia.org/wiki/SubRip)
+- [WebVTT Format Guide](https://developer.mozilla.org/en-US/docs/Web/API/WebVTT_API)

examples/provider-elevenlabs/alignment/promptfooconfig.yaml

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+# yaml-language-server: $schema=https://promptfoo.dev/config-schema.json
+description: ElevenLabs Forced Alignment - Subtitle generation
+
+# Alignment uses audio files + transcripts - pass via vars
+prompts:
+  - '{{transcript}}'
+
+providers:
+  # Basic alignment (JSON output)
+  - id: elevenlabs:alignment:json
+    label: Alignment (JSON)
+
+  # SRT subtitle format
+  - id: elevenlabs:alignment:srt
+    label: Alignment (SRT Subtitles)
+
+# Default test configuration
+defaultTest:
+  # All tests will require alignment to complete
+  assert:
+    - type: not-contains
+      value: error
+
+tests:
+  - description: Align Armstrong moon landing speech
+    vars:
+      audioFile: examples/provider-elevenlabs/stt/audio/sample1.mp3
+      transcript: "That's one small step for man, one giant leap for mankind."
+      format: json
+    assert:
+      - type: javascript
+        value: output.includes('words')
+      - type: not-contains
+        value: error
+
+  - description: Align Armstrong to SRT format
+    vars:
+      audioFile: examples/provider-elevenlabs/stt/audio/sample1.mp3
+      transcript: "That's one small step for man, one giant leap for mankind."
+      format: srt
+    assert:
+      - type: javascript
+        value: output.includes('-->') && output.includes('small step')
+
+  - description: Align sample2 hello message
+    vars:
+      audioFile: examples/provider-elevenlabs/stt/audio/sample2.wav
+      transcript: "Hello. What's today's date? Could you please let me know?"
+      format: json
+    assert:
+      - type: javascript
+        value: output.includes('words')
+      - type: not-contains
+        value: error