Help wanted: add stable 2026 proceedings adapters for NeurIPS, IJCAI, and KDD

[MicroMilo]

Why

These conference series are registered in the census but remain conference-level pending because a complete first-party 2026 paper list has not been imported.

Definition of done

• Use only the official conference site, official proceedings, conference OpenReview group, or formal publisher.
• Import the complete official list with track metadata and source timestamps.
• Preserve an explicit included, excluded, pending, or duplicate disposition for every record.
• Never substitute an arXiv list for proceedings.
• Add source fixtures and tests for pagination, retries, deduplication, and partial publication.
• Run make census-split, make audit-report, make check, and make site-check.

Useful entry points

• scripts/build_conference_census.py
• scripts/source_fetcher.py
• scripts/census_store.py
• docs/source-fetching.md
• data/audit/2026-conference-census/index.yaml

One conference adapter per pull request is welcome.