Add rate limiting for search

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

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

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

The issue names search and middleware but no files, tests, or entry points. Start by locating the search and middleware entry points, then clarify the intended rate-limit behavior and error-message requirements. Done should be defined by maintainers with tests covering the agreed behavior.

Written by the indexing model from the issue text.