chore(gitignore): add DataSet/ to prevent customer-PII re-commit

The previous entries only matched DataSet1/ and DataSet2/, missing the
unsuffixed DataSet/ directory that contained 225 MB of real Orange
customer documents (names, addresses, urbanism refs). History was
purged with git-filter-repo; this guard prevents it from coming back.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitignore

@@ -55,6 +55,7 @@ Thumbs.db
 # ────────────────────────────────────────────────────────────────────────────
 # Training datasets: real Autorisations, Mandats, Plans, Certificats with
 # names, addresses, phone numbers, urbanism references.
+DataSet/
 DataSet1/
 DataSet2/