fix: Add missing maps module and scope gitignore rules

maps/ gitignore rule was catching backend-nest/src/modules/maps/.
Scoped to /maps/ (root only) so runtime data is still ignored
but source code isn't.

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

.gitignore

@@ -25,9 +25,9 @@ Thumbs.db
 docker/pg_data/
 docker/nats_data/
 
-# Maps and backups (runtime data)
-maps/
-backups/
+# Maps and backups (runtime data, top-level only)
+/maps/
+/backups/
 
 # Logs
 *.log