chore: review which stored settings the CrowdSec export includes #1539

What: the export archives the configuration tree, including notification settings and database connection settings in config.yaml. Decide which of these belong in a portable export and document or filter the rest.
Where: ExportConfig in backend/internal/api/handlers/crowdsec_handler.go.
Suggested approach: list what the export contains, decide an allowlist/denylist consistent with the editor's hidden-file rule, and word the user docs as "account and connection details are not included" only for what is actually excluded.
Found while planning #1532-#1534. Severity: low.