Add a /model_resolver/search-cancel/{progress_id} endpoint with a
SearchCancelled exception so in-flight source searches abort cleanly on
batch cancel. Track sourceProgressIds alongside sourceControllers so the
frontend can cancel backend progress polls. Rework CivArchive extraction
with robust __NEXT_DATA__ parsing, hash-page file resolution, model-link
scraping, confidence-based candidate filtering, and expanded type maps.
Add conftest.py for pytest path setup, update .gitignore for scratch/,
and refresh huggingface-author-index.json.
