The >= 4 digit guard was a Lansing-specific assumption that excluded ballot
numbers shorter than 4 digits. Changed to require only 1+ digit and use the
full numeric value so all precincts (e.g. FH 2-44) appear in the report.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Groups raw ballot numbers by precinct, extracts the last 4 digits of each
(matching the Lansing PS analysis script), then reports min/max and any
gaps in the range. Report rows are now sorted descending by precinct.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>