- Introduced `TaskConfig` struct to manage task-related configurations.
- Implemented `TaskTool` for creating and managing subagents for complex tasks.
- Added `TaskSession` and `TaskRepository` for handling task sessions and persistence.
- Created `DefaultSubAgentRuntime` to execute tasks with timeout and history support.
- Enhanced `ToolContext` to include `subagent_description` for better context tracking.
- Implemented error handling for task execution and session management.
- Updated `ToolRegistryFactory` to register task tools conditionally based on configuration.
- Added prompt builders for subagent tasks to improve interaction clarity.
- Introduced `SkillProvider` trait to abstract skill-related functionalities.
- Replaced `SkillRuntime` with `EmptySkillProvider` in `AgentLoop` for default behavior.
- Updated `AgentFactory` to accept `SkillProvider` instead of `SkillRuntime`.
- Created `SessionHistory` struct to manage chat histories and interactions.
- Added `MemoryRepository`, `SchedulerJobRepository`, and `SkillEventRepository` traits for better storage abstraction.
- Refactored tools to use new repository traits for memory and scheduler management.
- Cleaned up session management logic by consolidating chat history handling into `SessionHistory`.
Co-authored-by: Copilot <copilot@github.com>