Use bind mounts for pgdata and dp_keys in docker-compose

Matches the production compose so the stack data lives next to the
compose file and can be backed up with the server. ticket_uploads stays
a named volume to avoid losing existing attachments on pull.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.dockerignore

@@ -6,6 +6,11 @@
 **/node_modules/
 frontend/dist/
 
+# Данные docker-compose (bind-маунты): в build context не нужны, а pgdata ещё и нечитаем
+# (владелец — uid postgres), сборка на нём падала бы
+pgdata/
+dp_keys/
+
 # VCS / IDE / env
 .git/
 .vs/