# Task ID: 37
# Title: Add Gemini Support for Main AI Services as Claude Alternative
# Status: done
# Dependencies: None
# Priority: medium
# Description: Implement Google's Gemini API integration as an alternative to Claude for all main AI services, allowing users to switch between different LLM providers.
# Details:
This task involves integrating Google's Gemini API across all main AI services that currently use Claude:

1. Create a new GeminiService class that implements the same interface as the existing ClaudeService
2. Implement authentication and API key management for Gemini API
3. Map our internal prompt formats to Gemini's expected input format
4. Handle Gemini-specific parameters (temperature, top_p, etc.) and response parsing
5. Update the AI service factory/provider to support selecting Gemini as an alternative
6. Add configuration options in settings to allow users to select Gemini as their preferred provider
7. Implement proper error handling for Gemini-specific API errors
8. Ensure streaming responses are properly supported if Gemini offers this capability
9. Update documentation to reflect the new Gemini option
10. Consider implementing model selection if Gemini offers multiple models (e.g., Gemini Pro, Gemini Ultra)
11. Ensure all existing AI capabilities (summarization, code generation, etc.) maintain feature parity when using Gemini

The implementation should follow the same pattern as the recent Ollama integration (Task #36) to maintain consistency in how alternative AI providers are supported.

# Test Strategy:
Testing should verify Gemini integration works correctly across all AI services:

1. Unit tests:
   - Test GeminiService class methods with mocked API responses
   - Verify proper error handling for common API errors
   - Test configuration and model selection functionality

2. Integration tests:
   - Verify authentication and API connection with valid credentials
   - Test each AI service with Gemini to ensure proper functionality
   - Compare outputs between Claude and Gemini for the same inputs to verify quality

3. End-to-end tests:
   - Test the complete user flow of switching to Gemini and using various AI features
   - Verify streaming responses work correctly if supported

4. Performance tests:
   - Measure and compare response times between Claude and Gemini
   - Test with various input lengths to verify handling of context limits

5. Manual testing:
   - Verify the quality of Gemini responses across different use cases
   - Test edge cases like very long inputs or specialized domain knowledge

All tests should pass with Gemini selected as the provider, and the user experience should be consistent regardless of which provider is selected.