security: harden gitignore and add config example files [v1.3.7]
- Expanded .gitignore: root venv, npx_cache, AI metadata (.remember, .claude),
data/ (SQLite DB), frontend/config/, frontend/public/icons/, certificates,
docker-compose.override.yml
- Removed backend/config/ldap_config.json from git tracking (contains real IPs/credentials)
- Added backend/config/ldap_config.json.example with placeholder template
- Updated backend/.env.example: added JWT_SECRET_KEY, ALLOWED_ORIGINS, DATA_DIR, LOGS_DIR
955b1e86e5