fix: remove .env.backup from git history and update .gitignore

- Remove .env.backup file containing hardcoded API keys from entire git history
- Add .env.backup and .env.*.backup patterns to .gitignore
- Prevents future accidental commits of backup files with secrets

IMPORTANT: Any API keys that were exposed in .env.backup should be revoked
and regenerated in the NVIDIA NGC portal.

Author: T-DevH

.gitignore

@@ -86,7 +86,9 @@ docker-compose*.bak
 .env.test.local
 .env.production.local
 .env.bak
+.env.backup
 .env.*.bak
+.env.*.backup
 secrets/
 *.pem
 *.key