Refactor worker manager, worker, and task system

- [ ] Refactor worker manager, worker, and task system (right now has a lot
of repetitive code)
- [ ] Make tasks be definable independent of ENUM / custom methods

Start by locating the worker manager, worker, and task system entry points and tracing how tasks currently depend on ENUM or custom methods. Map the repeated code and clarify the intended task definition boundary before changing anything. Done means the refactor scope is agreed and tasks can be defined independently of ENUM or custom methods.

Written by the indexing model from the issue text.