CLAUDE: Update .gitignore to explicitly ignore .env files

- Add .env and environment file patterns
- Add database backup patterns
- Ensures sensitive configuration is never committed

.gitignore

@@ -61,3 +61,13 @@ docker-compose*
 venv
 .claude/
 CLAUDE.md
+
+# Environment variables (NEVER commit these!)
+.env
+.env.local
+.env.*.local
+
+# Database backups
+*_backup_*
+*.bak
+*.backup