- Add IncludeServerSideToolInvocations field to GeminiToolConfig to prevent dropping client tool settings. - Fix HTTP 400 error when mixing built-in tools (e.g. Google Search) with function calling on Gemini 3.6/3.7 models. - Add serialization/deserialization unit test TestGeminiToolConfig_IncludeServerSideToolInvocations. Fixes #5709