- Introduced `claudeFastModeBeta` constant and logic to append it conditionally based on the `speed` attribute in the request body.
- Ensured `fast-mode-2026-02-01` beta inclusion only when explicitly requested or if the `speed` is set to `fast`.
- Updated `applyClaudeHeaders` to dynamically handle fast-mode beta and adjust headers accordingly.
- Enhanced beta extraction and addition with a new helper `appendClaudeFastModeBeta`.
- Improved flexibility in beta handling by preserving requested overrides while ensuring compatibility with default configurations.
Closes: #4703
- Replaced instances of `thinking.ApplyThinking` with `helps.ApplyRequestThinking` across all executors for consistency.
- Updated `applyGeminiInteractionsThinking` to accept `cliproxyexecutor.Request` and `Options`.
- Centralized logic for request thinking application to `helps` package for improved maintainability.
Closes: #4618
- Removed deprecated interceptor and executor-related methods, including `callRequestInterceptor`, `callResponseInterceptor`, and `callStreamChunkInterceptor`.
- Consolidated unused logic and pruned redundant imports to streamline `adapters.go`.
- No functional changes.
