fix(interpreter): commit src/datafusion/ — an unanchored local exclude rule hid it

The repo-root DataFusion clone is ignored via .git/info/exclude with the bare
pattern `datafusion/`, which matches at any depth and silently swallowed the
refactor's src/datafusion/ move (local builds passed off the working tree; CI
got a commit without the module). Exclude rule anchored locally to /datafusion/.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: ahrzb