create mruby-task gem directory structure with:
- mrbgem.rake: gem specification with task scheduler define
- include/task.h: tcb structure and core scheduler declarations
- src/task.c: implementation skeleton with empty method stubs
- mrblib/task.rb: ruby api documentation and task::stat class
all methods have empty bodies ready for implementation.
Co-authored-by: Claude <noreply@anthropic.com>