fix: validate search query input

[dtopenclaw]

Summary

• normalize search query input by trimming valid string values
• reject repeated/non-string q parameters before they reach the search service
• reject search queries longer than 200 characters with a 400 response
• make the API test script target concrete test files under Node 22
• add focused API coverage for trimming, long-query rejection, and repeated-parameter rejection

Validation

• npm test

Fixes #5958