* add gemini web search provider
* fix(web): prefer free providers before Gemini in auto mode
* fix(web): expose gemini api key and model settings
* fix(web): prefer configured providers before Gemini in auto mode
* fix(web): satisfy gemini lint checks
* fix(web): address gemini provider review feedback
* test(web): align auto-provider expectations
* fix(web): let gemini ignore search range