chore: gitignore .env backups/.env.local

Keep stray .env.bak*/.env.local files (e.g. created while wiring OIDC) out of
version control so credentials are never committed.

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

.gitignore

@@ -6,3 +6,5 @@ coverage.out
 
 # Docker volume data (bind-mounted under the repo; never committed)
 /.volumes/
+.env.bak*
+.env.local