### CHANGES
- Add `sourcesHeader` constant for citation section title.
- Use `strings.Builder` to construct result efficiently.
- Append sources header and citations in result builder.
- Update `ret` to use constructed string from builder.
## CHANGES
- Add --search flag to enable web search
- Add --search-location for timezone-based results
- Pass search options through ChatOptions struct
- Implement web search tool in Anthropic client
- Format search citations with sources section
- Add comprehensive tests for search functionality
- Remove plugin-level web search configuration
### CHANGES
- Introduce local `chat` package for message abstraction
- Replace sashabaranov/go-openai with official openai-go SDK
- Update OpenAI, Azure, and Exolab plugins for new client
- Refactor all AI providers to use internal chat types
- Decouple codebase from third-party AI provider structs
- Replace deprecated `ioutil` functions with `os` equivalents
## CHANGES
- Add NeedsRawMode to Vendor interface
- Implement NeedsRawMode in all AI clients
- Return false for all implementations
- Support model-specific raw mode detection
- Enable future raw mode requirements
CHANGES
- Upgrade `anthropic-sdk-go` dependency to version `v1.2.0`.
- Integrate new Anthropic Claude 4 Opus and Sonnet models.
- Remove deprecated Claude 2.0 and 2.1 models from list.
- Adjust model type casting for `anthropic-sdk-go v1.2.0` compatibility.
- Refresh README: announce Claude 4, update date, fix links.
## CHANGES
- Upgrade Anthropic SDK from alpha.11 to beta.3
- Update API endpoint from v1 to v2
- Replace anthropic.F() with direct assignment
- Replace anthropic.F() with anthropic.Opt() for optional params
- Simplify event delta handling in streaming
- Change client type from pointer to value type
- Update comment with SDK changelog reference
## CHANGES
- Updated anthropic-sdk-go from v0.2.0-alpha.4 to v0.2.0-alpha.11
- Added Claude 3.7 Sonnet models to available model list
- Added ModelClaude3_7SonnetLatest to model options
- Added ModelClaude3_7Sonnet20250219 to model options
- Removed ModelClaude_Instant_1_2 from available models
- Enable and improve custom API base URL configuration
- Add proper handling of v1 endpoint for UUID-containing URLs
- Implement URL formatting logic for consistent endpoint structure
- Clean up commented code and improve configuration flow
