The previous pass only stripped the duplicate-header block when both
\endfirsthead and \endhead were present. Pandoc emits one or the other
standalone for some table shapes, and any survivor pulls longtable
internals (\LT@echunk, \LT@max@sel) into the rewritten tabular and
breaks the build. Mop up each directive independently.

Bumps to 0.0.13.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>