- Add progressCallback parameter to extractFromEmbeddedJSON and extractFromDOM
- Pass onProgress callback from extractWithStrategies to all strategies
- Fix legacy strategy to use correct callback variable name
- Verify extractViaGraphQL correctly returns null thumbnail
This fixes ReferenceError that was preventing all extraction methods from working.
All extraction strategies now properly emit thumbnail progress events via SSE.
Closes: FixProgressCallbackUndefinedErrors
2de5567682