chore: added EOT 2024 via hive partitioning (#3)

* chore: added EOT 2024 via hive partitioning

* chore: rename host-index hive partition eot=<year> to crawl=<year>

* fix: replaced internal with public S3 bucket prefix

* docs: restore full url-index walkthrough, adapt to crawl partition

The hive-partition rename commit had condensed the url-index section down
to two examples, dropping the original step-by-step investigations. Restore
the full congress.gov 4xx walkthrough and the irs.gov LOTE walkthrough
(pinned to crawl = 'EOT-2020', view renamed eot2020_url -> eot_url) and keep
the EOT-2024 cross-crawl comparisons as additive extensions.

* fix: host-index crawl partition values are EOT-YYYY, not bare year

The hive partition is crawl=EOT-2020 / crawl=EOT-2024 (matching the url
index), not crawl=2020 / crawl=2024. The crawl column is therefore VARCHAR,
and host-index filters use crawl = 'EOT-2020'. Update select.py partition
list, the README paths, schema box, filters, prose, and the regenerated
result boxes.

Author: malteos