- Changed the query in the `TestSerpAPIProviderWithAssistantConfig` from "Yao App Engine" to "golang programming language" to align with updated test expectations.
- Updated the expected result assertion to match the new query, ensuring the test accurately verifies the functionality of the search handler.
- Introduced new environment variables for TAVILY_API_KEY, SERPAPI_API_KEY, and SERPER_API_KEY in both `pr-test.yml` and `unit-test.yml` workflows to support additional search providers.
- Updated `DESIGN.md` to reflect the inclusion of SerpAPI as a search provider, detailing its usage and configuration options, including support for multiple search engines.
- Enhanced the `builtinSearch` function in `handler.go` to accommodate the new SerpAPI provider, ensuring proper handling of search requests.
- Revised the `WebConfig` struct in `config.go` to include an `Engine` field for specifying the search engine when using SerpAPI, improving flexibility in search configurations.
- Updated documentation to clarify the roles of new search providers and their integration within the search module, ensuring comprehensive guidance for developers.
