Add rate limiting for search

**Problem**
When working with core, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files, tests, entry points, or implementation details are named. First reconcile the title's search rate-limiting request with the body, which instead asks for more descriptive core error messages; define the affected search path, limits, and acceptance criteria before work can start.

Written by the indexing model from the issue text.