Refactor: Change `FuncNode.name` to `FuncNode.func_id`

[thorwhalen]

The name name is problematic since it should be unique and used for internal purposes. More like a reference or id.

This refactor can be done while keeping back compatible (for now) by creating a @property called name that points to func_id.

Other name option: fid.

Could also have a **kwargs that keeps the possibility for using name in __init__ but I'd rather not.

Further (perhaps this should be a separate issue?) we may want to use func_id instead of the FuncNode instance itself in the DAG.graph. It's more readable, and less problems with hashing, sorting, etc.

[thorwhalen]

Not done yet: FuncNode.name (meshed/base.py:256, name: str = field(default=None)) is still the actual field; there's no func_id attribute or back-compat name property pointing to it. (A local variable named func_id exists inside one factory helper, but that's unrelated to the class API.) Related to #29 and #41, which both touch the same naming/identity surface -- worth doing together if picked up. Leaving open; this is an architecture decision (attribute rename + back-compat shim + DAG.graph keyed by id instead of instance) that changes a public, widely-used class, so didn't attempt it here.