Add rate limiting for import

**Description**
Currently config lacks proper timeout support.

**Proposed solution**
Add configurable timeout with sensible defaults.

**Priority**: Low/Medium

No file, test, or entry point is named. First reconcile whether the requested change is import rate limiting or configurable timeout support, then locate the import handling and configuration definitions. Done means the intended behavior, defaults, and configuration surface are specified and covered by tests.

Written by the indexing model from the issue text.