- Added a Go scheduler plugin demonstrating CLIProxyAPI capabilities, such as `plugin.register`, `plugin.reconfigure`, and `scheduler.pick`.
- Implemented methods for plugin configuration, built-in scheduler delegation (`fill-first`, `round-robin`), dynamic candidate selection, and error handling.
- Extended `pluginhost` with scheduler handling, candidate normalization, and fallback mechanisms.
- Included examples, tests, and detailed documentation for scheduler usage and implementation.
- Implemented `RequestInterceptor`, `ResponseInterceptor`, and `StreamChunkInterceptor` capabilities.
- Added `sanitizePluginMetadata` to clean metadata for RPC compatibility.
- Enhanced interceptor chaining, error handling, and test coverage.
- Updated plugin configuration to register and dispatch interceptor methods.
- Removed `examples/plugin/main.go` and `internal/pluginhost/loader_plugin.go` after migrating to a more modular system.
- Introduced `streamBridge` in `internal/pluginhost/stream_bridge.go` for efficient stream handling and communication.
- Added examples of `thinking` plugins written in both Rust and Go under `examples/plugin/thinking`.
- Enhanced test coverage for plugin host system changes, including stream chunk translation and thinking logic.
- Improved API compatibility and ensured backward-compatible upgrades for plugin execution.
