Keep database snapshots out of the repository

Before applying the five pending migrations I took a full snapshot of the
live database — every table plus the source of all 61 functions. It sits in
.backups/ and holds 852 personnel records, so it must never be committed.

The ignore rule comes first, on its own, rather than riding along with the
next change: a snapshot that is already staged when someone remembers to
add the rule is a snapshot that has been in a commit.

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

.gitignore

@@ -54,3 +54,6 @@ next-env.d.ts
 # seeded DB — can carry HR data or use SUPABASE_SERVICE_ROLE_KEY; never commit)
 .scratch_*
 /.scratch_shots/
+
+# Datenbank-Sicherungen (enthalten Personendaten) – nie committen.
+.backups/