Introduce a distributed task execution system for gRPC runners. This includes:
- A `TaskBus` for cluster-mode task dispatching via Redis Pub/Sub.
- A `RunnerRegistry` to track active runner instances in Redis.
- Support for both standalone and cluster modes via configuration.
- Refactored `RunnerHub` and `TaskManager` to use a `TaskDispatcher` interface, decoupling task submission from local execution.
- Added distributed locking to `HotRankWorker` to ensure only one instance performs periodic hot rank recalculations in a multi-instance deployment.
- Updated dependency injection (Wire) to support the new runner components and registry.