Instantiate finite-family coherence on typed systems #294

Connect the abstract finite-family contract to the existing tensorAll, parallelAll and parallel converter operations.

Acceptance:

• Discharge the contract with existing systems laws, including parallelAll_reindex and parallelAll_optionSplit where available locally.
• Preserve existing interfaces, domains, sampling semantics and public operations.
• Check empty, singleton and heterogeneous families; the abstract equations specialize to the existing typed equations.

Depends on: #293. Related: #40, #228.